Scientists have identified enormous finned "kraken" octopuses that may have reached up to 62 feet (19 meters) long. The behemoths prowled the oceans during the Cretaceous and could be the largest invertebrates ever discovered.

Fossil jaws revealed distinctive markings that suggest these kraken-like octopuses used their powerful jaws to crush hard-shelled prey. That, combined with their gigantic size and evidence of intelligence, put them top of the marine food chain, according to a study published Thursday (April 23) in the journal Science.

This finding suggests scientists need to rethink the oceanic pecking order during the Cretaceous period (145 million years to 66 million years ago).

"These findings revise the view of the Cretaceous ocean as a world dominated only by large vertebrate predators," study co-author Yasuhiro Iba, a paleontologist at Hokkaido University in Japan, told Live Science in an email. "They show that giant invertebrates — octopuses — also occupied the top of the food web."

Other experts say these size estimates are the upper end of a large possible range. Even so, the discovery raises questions about the oceanic landscape of the Cretaceous, such as how these species could grow so large, and whether even larger marine species existed after the Cretaceous period, they said.

Hunting down the apex predators

Species at the top of the food chain shape ecosystems, with their prey responding by evolving protection measures, such as hard shells. Understanding which species held the apex position is essential for understanding how Cretaceous marine ecosystems functioned, Iba said.

Until now, the top dogs were all assumed to be vertebrates, such as mosasaurs and plesiosaurs. However, the lack of preserved evidence from soft-bodied octopuses has made their position in the Cretaceous food chain a complete mystery, the authors wrote in the study.

"Octopuses are known today as highly intelligent animals, but they are extremely difficult to study in deep time because they lack hard external shells," Iba said. "A major motivation for this study was to reveal this almost invisible history of octopuses."

For the study, the researchers reassessed 15 fossilized octopus jaws previously unearthed in Japan and Vancouver Island. They also discovered 12 new Cretaceous fossil octopus jaws in Japan using state-of-the-art digital fossil-mining technology. Combined, these revealed two species of extinct finned octopuses: Nanaimoteuthis jeletzkyi and Nanaimoteuthis haggarti.

The N. jeletzkyi fossils were unearthed in rocks dating to between 100 million and 72 million years ago, pushing back the oldest known octopuses by around 5 million years, and finned octopuses by 15 million years, the authors wrote in the study.

The team then compared the size, shape and wear marks on all 27 jaws with modern-day octopuses to reconstruct their body size, feeding behavior and position in the food web.

The size of living octopuses' mantles — the bulging organ sac sitting above their eyes — is related to the length of their jaws. The total length of living long-bodied finned octopuses is around 4.2 times their mantle length.

Iba and his colleagues used this to estimate just how bulbous N. jeletzkyi and N. haggarti mantles were. From there, they could calculate their possible total length of the long-dead creatures.

Based on the largest jaw for each species, the team estimated the maximum length of N. jeletzkyi was around 10 feet to 26 feet (3 m to 8 m), while N. haggarti was approximately 23 feet to 62 feet (7 m to 19 m). This makes N. haggarti potentially the largest invertebrate discovered to date, and "among the largest body sizes of all organisms in the Cretaceous oceans," the authors wrote in the study. (Modern-day giant squid, Architeuthis dux, reach around 40 feet (12 m) long, and Cretaceous mosasaurs reached approximately 56 feet (17 m) long.)

The kraken jaws also showed signs of intensive wear, with patterns indicating that these animals were dismantling hard-shelled prey using their whole jaws. The front tips on both species' jaws were ground down on one side by as much as 10% of their total size, based on reconstructions. This lopsided loss suggests lateralized behavior, which is linked to being brainier, the authors said in the study.

"These were not just giant octopuses, but giant, intelligent, and highly formidable marine predators," Iba said.

However, while experts applauded the digital fossil-hunting techniques used in the study, they questioned the size estimates of each species.

The study researchers estimated the size of N. jeletzkyi and N. haggarti using "error prone" averages of jaw-to-mantle and mantle-to-total-body size relationships of living species, meaning their results produced a large possible size range for both species, René Hoffman, a paleontologist focusing on fossil cephalopods at the Ruhr University Bochum in Germany, told Live Science in an email.

Their enormous size also does not necessarily mean that these invertebrates were the top predator, Hoffman added.

Christian Klug, a professor of paleontology and expert in cephalopod evolution at the University of Zurich in Switzerland, agreed. While the estimates are within the range of what is possible, he said that some uncertainty is inevitable. "There is no doubt that Nanaimoteuthis was a huge and efficient predator," he told Live Science in an email, but only focusing on the maximum total size "lets one forget that it is conceivable that they may have not reached ten meters."

Are you a sucker for cephalopod science? Test your knowledge with our Octopus quiz!

Octopuses are a useful reminder that complex life can be organized in very different ways. With no backbone, their anatomy departs sharply from the body plans many people are familiar with. They are classified as cephalopods, a class of animals that includes squid, nautiluses and cuttlefish.

Octopuses can rapidly change the color and texture of their skin, manipulate objects with remarkable dexterity, and navigate environments that demand both flexibility and control. Scientists study these traits because they offer insight into how perception, movement and problem-solving evolved in invertebrates.

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Cephalopod evolution has long had a missing chapter in its story: how did squid-like ancestors give rise to today's octopuses? The answer, it turns out, was floating in the deep sea all along.

With its glowing ghostly eyes, eight arms like its octopus cousins and a dark ruby coloring to match, the elusive vampire squid (Vampyroteuthis infernalis) has finally revealed its genetic secrets.

In a study published Nov. 27 in the journal iScience, researchers sequenced the genome of Vampyrotheuthis and discovered its chromosomes still resemble those of squids and cuttlefish — despite belonging to the octopus order. This discovery hints at what the common ancestor of modern squids and octopuses may have looked like at the genetic level 300 million years ago when octopus and squid evolutionarily diverged. The researchers described the vampire squid as a "living fossil."

On the cephalopod evolutionary tree, the vampire squid belongs to the group that includes octopuses, but underwent a "very ancient split" from the rest of the clade, study lead author Oleg Simakov, a researcher at the Department of Neuroscience and Developmental Biology in the University of Vienna, Austria, told Live Science in an email.

After acquiring a tissue sample from a vampire squid collected as bycatch in the West Pacific Ocean from a research cruise, the researchers used a genetic analysis platform called PacBio to sequence the DNA of the sample. Unfortunately, there were no other vampire squid samples to compare it to, due to their rarity. Using PacBio, the researchers compared the vampire squid's genome to that of other cephalopods like the Argonaut (Argonauta hians), the common octopus (Octopus vulgaris) and the curled octopus (Eledone cirrhosa).

The findings revealed the vampire squid has an 11 billion-base-pair-long genome, almost four times the size of the human genome — and the largest cephalopod genome sequenced to date.

While modern octopuses have DNA that consistently gets reshuffled, resulting in some chromosomal mixing, the researchers found that the vampire squid's genome kept much of its ancestral, squid-like chromosomal arrangement. Essentially, it's an octopod that genetically looks like an ancient squid.

The vampire squid has had a long history of being misunderstood. When it was initially discovered in 1903, it was thought to be a cirrate octopus due to its unique webbing between its arms. In the 1950s however, scientists reclassified it as its own group, belonging to neither octopus nor squid but in the order Vampyromorphida, so named because it looks like it's wearing a vampire-like cloak.

The finding is welcome news for cephalopod scientists as it is "nice to have resolved" why vampire squids retain much of their ancestral, squid-like traits, said Bruce Robison, senior scientist at the Monterey Bay Aquarium Research Institute (MBARI) who was not involved in the research.

Part of what makes the fully sequenced genome so valuable is how hard it is to study vampire squids, mainly "because they live in a habitat that is difficult to access, they are solitary, rare, and do not survive well in captivity," Robison said. "Some people think that we can just dive into deep water, and find one whenever we like, which is definitely not the case."

He added that the findings "reinforce the notion held by some of us that vamps would be the key to the puzzle. They are interesting to study because they are such cool animals, and because they just look like they are hiding secrets."

Scientists have filmed a never-before-seen species of deep-sea squid burying itself upside down in the seafloor — a behavior never documented in cephalopods. They captured the bizarre scene while studying the depths of the Clarion-Clipperton Zone (CCZ), an abyssal plain in the Pacific Ocean targeted for deep-sea mining.

The team described the encounter in a study published Nov. 25 in the journal Ecology, writing that the animal appears to be an undescribed species of whiplash squid. At a depth of roughly 13,450 feet (4,100 meters), the squid had buried almost its entire body in sediment and was hanging upside down, with its siphon and two long tentacles held rigid above the seafloor.

"The fact that this is a squid and it's covering itself in mud — it's novel for squid and the fact that it is upside down," lead author Alejandra Mejía-Saenz, a deep-sea ecologist at the Scottish Association for Marine Science, told Live Science. "We had never seen anything like that in any cephalopods. … It was very novel and very puzzling."

Mud covering and burial have been seen in octopuses and cuttlefish, and even in shallower-water squid species before. However, these behaviors had never been documented in a deep-sea squid before — and never upside down.

"It was so exciting and unexpected to observe burying behaviour in a deep-sea squid, something that has never been seen before!" study co-author Bethany Fleming, a researcher at the University of Southampton and the National Oceanography Centre in the U.K., said in a statement emailed to Live Science.

Masquerade on the seafloor

The encounter happened during the SMARTEX project, a U.K.-led expedition to study how deep-sea mining might affect life in the CCZ. The team's remotely operated vehicle (ROV) was filming across a commercial exploration area, when the squid appeared underneath it, with its tentacles looking like the stalks of glass sponges or large tube worms that dot the seemingly barren abyssal plain.

At first the squid underneath the ROV, seemingly unaware of its existence. It was then that the researchers realized it was a type of squid due to its movements and body traits. However, the squid then seemed to disappear from camera.

“[Fleming] first saw this and said ‘wait a minute, is the squid actually there?’ Because the only thing we could see were two white things sticking out.” Mejía-Saenz said.

The case of the disappearing squid was quickly solved when the researchers realized it had buried itself. From watching the squid, the team believes it is camouflaging itself, proposing potentially two reasons why it had buried itself with its tentacles poking out: it was trying avoid predators like beaked whales or it had seen crustaceans, its favorite prey, crawling around the glass sponges in the area and was mimicking the sponges with its tentacles to attract a snack. "We thought, 'okay then if the sponge is attracting the crustacean and the squid is imitating the sponge and it eats the crustacean, that would make sense'," Mejía-Saenz said.

If that's right, the squid may be using a strategy biologists call masquerade — looking like an inedible object so predators ignore it — combined with a booby-trap for prey. In the food-poor abyss, that kind of ambush could be a smart energy trade-off, as animals waste less energy waiting for food to come to them than they would chasing it, all while remaining invisible to nearby threats.

Jim Barry, a senior scientist at the Monterey Bay Aquarium Research Institute (MBARI) in California who was not involved in the study, agreed that the squid appears to be mimicking the glass sponges seen in the CCZ. "When the squid assumes the charade behavior it is similar to some seafloor invertebrates (sponges, soft corals, polychaete worms) that inhabit the region," he told Live Science in an email.

Why abyssal squid are so rarely seen

Deep plains like the CCZ cover vast areas of seafloor, yet they remain among the least-explored habitats on the planet. "The ocean is huge," Mejía-Saenz said, and abyssal plains "are one of the least explored parts of the ocean."

Even in this comparatively well-studied zone, the team's broader survey found just 33 cephalopod encounters across roughly 3,100 miles (5,000 kilometers) of ROV tracks. That tiny tally helps explain why behaviors like mud-covering masquerade are only now coming to light.

"Considering the very limited observations that have been made at abyssal depths, it may not be surprising to discover a new species," Barry said. "Abyssal squids are very rare and those with a mimicking behavior are even less known to science. …the main reason we know so little about deep sea cephalopods is [the] very limited amount of effort that has gone into exploring the deep-sea."

Mining into the unknown

What makes this single squid especially worrying is where it was seen. The CCZ is the primary target for the proposed deep-sea mining of nickel, cobalt, manganese and other metals used in batteries.

"The reason why we know so much about the CCZ is because there are commercial interests on it," Mejía-Saenz said. To retrieve the valuable minerals, mining vehicles would stir up sediment plumes that blanket nearby life. "Disturbance to the seafloor would have negative consequences mostly likely for these animals," she said. "The extent of those consequences, we still don't know."

Barry said we increasingly depend on deep-sea resources. In potential mining zones, "there is much at stake," he said, "and it is imperative that we understand at a minimum what life inhabits these sites and how vulnerable these biological communities are to human activities."

Bruce Robison, an MBARI scientist who was not involved in the study, said discoveries like this mud-covered squid highlight the limits of our knowledge.

"Deep-sea squid are fast, agile, and wary, so they only let us see them when they want to, or when they just don't care," he told Live Science in an email. "We must have observed only a very small fraction of their behaviors. It's always surprising to learn about a new (to us) tactic that squids have in their bag of tricks."

Ocean researchers have discovered thriving alien-like communities filled with tube worms, mollusks and spiky white creatures at the bottom of ocean trenches in the northwest Pacific Ocean.

The discovery, by a Chinese-led research team using a submersible at depths of around 31,000 feet (9,500 meters), represents the deepest and most extensive communities of chemical-reaction-powered life-forms known to exist on Earth.

These bizarre creatures survive in extreme conditions. They sustain tremendous amounts of pressure in total darkness and get their energy from chemical reactions rather than from the sun. The researchers' findings, published Wednesday (July 30) in the journal Nature, suggest that this chemosynthetic life may be more widespread than scientists' previously thought, according to a statement released by the journal's publisher, Springer Nature.

The newly identified communities were in trenches in the hadal zone — the region of the ocean below about 20,000 feet (6,000 m). Hadal trenches include some of the deepest parts of the ocean and are largely unexplored.

"It's exciting — especially for a deep sea scientist — to go to a place that human beings have not explored," Xiaotong Peng, one of the study's lead authors and deputy director of the Institute of Deep-sea Science and Engineering at the Chinese Academy of Sciences, told BBC News. "It's a great opportunity to discover new things. And what we saw was quite amazing."

Related: The Mariana Trench is home to some weird deep sea fish, and they all have the same, unique mutations

Sunlight doesn't reach deep into the ocean, so life on and near the deep seafloor can't use photosynthesis — the process by which plants, algae and some bacteria convert sunlight into energy. Researchers have long proposed that the hadal trenches host communities powered by other chemical reactions that rely on hydrogen sulfide and methane emanating from the seafloor, but such chemosynthesis-based communities are rarely documented, according to the study.

Most of the deep ocean remains unexplored. In fact, a study published in May found that humans have explored just 0.001% of the deep seafloor (below 656 feet, or 200 m) — an area roughly the size of Rhode Island.

For the new study, the researchers worked their way along the Kuril-Kamchatka and Aleutian trenches, covering depths ranging from 19,029 to 31,276 feet (5,800 to 9,533 m). This region is very geologically active and hosts many volcanically and seismically active sites, according to the study. Despite the hostile environment, the newly documented communities were flourishing.

"The communities are dominated by marine tubeworms called siboglinid polychaetes and molluscs called bivalves, which synthesize their energy using hydrogen sulfide and methane seeping out of faults in the tectonic plate," Springer Nature representatives wrote in the statement.

Octopuses have gotten a reputation for being cunning camouflagers and intelligent creatures. But some are known for a more ominous reason: They're deadly.

One group — the blue-ringed octopus (genus Hapalochlaena) — is especially dangerous. But what makes this creature so lethal?

Blue-ringed octopuses carry a killer concoction called tetrodotoxin (TTX), a potent neurotoxin that can paralyze living things, including humans. Tetrodotoxin is most famously known from pufferfish — improperly prepared "fugu" can kill those who eat it. Tetrodotoxin is 1,200 times more toxic to humans than cyanide and it has no known antidote.

All four of the octopus species in the genus Hapalochlaena have tetrodotoxin, making them the four most venomous species of octopus: the greater blue-ringed octopus (H. lunulata), the southern or lesser blue-ringed octopus (H. maculosa), the blue-lined octopus (H. fasciata) and the common blue-ringed octopus (H. nierstraszi). These cephalopods, with their iridescent blue circles, are indeed beautiful, but also dangerous.

All octopods — a group of marine animals that includes octopuses — have venom, but some of these animals' venom is more potent than others', said Michael Vecchione, an adjunct zoologist at the Smithsonian Museum of Natural History. "The blue-ringed is perhaps the most venomous," he told Live Science in an email, in part because it lives in shallow water teeming with predators that may hope to feast on this octopus. Its venom is a natural defense.

"The venomous secretions are among a broad spectrum of naturally occurring toxins produced by octopods," Vecchione added. However, blue-ringed octopuses don't actually make tetrodotoxin on their own. Rather, symbiotic bacteria in their salivary glands produce it, the Australian Institute of Marine Science reports.

Related: How many hearts does an octopus have?

These octopuses reside in coral reefs and on rocky seafloors in the Pacific and Indian oceans. They hang out at depths of around 66 to 164 feet (20 to 50 meters) deep, depending on the species. They're also tiny, measuring between 5 and 9 inches (12 to 22 centimeters) long, including their arms.

"It does make sense that such a small octopus would have to have such impressive abilities to defend itself," Bret Grasse, manager of cephalopod operations at the University of Chicago Marine Biological Laboratory, told Live Science.

This potent venom comprises a number of compounds — like histamine, acetylcholine and dopamine — but its primary component is tetrodotoxin. It acts on nerve tissue as a neural inhibitor by blocking sodium channels — proteins in nerve cells that are essential to communication between these cells and muscles. When tetrodotoxin acts on these channels, it can stop a creature's lung muscles from breathing and even their heart from beating.

This venom comes in handy for fighting predators and capturing prey. Blue-ringed octopuses commonly deploy their venom through direct bites. Although researchers have found a blue-ringed octopus's venom throughout its body, like in its gills and the sac that contains its internal organs, it's most concentrated in the posterior salivary gland, Grasse said.

They can also disperse the venom into the surrounding water. When nearby creatures — predators or prey — breathe, they take in the toxic water, which "can start to slow their motor activity and paralyze them," Grasse said.

But the venom isn't just weaponry; blue-ringed octopuses also employ it in mating, Grasse said. As with other animals, the female blue-ringed octopus is "substantially" larger than the male — sometimes even three to five times larger — so the male faces risks when mating, including the danger of being cannibalized.

Although the blue-ringed octopus has some resistance to its own toxins, it's not completely immune. So the male can temporarily paralyze larger females with venom long enough to transfer a sperm packet.

The females also incorporate venom into their egg laying, Grasse said. They layer their eggs with the toxin to deter predators.

It's uncommon for a human to get bitten by a blue-ringed octopus, Grasse said. There are at least three reported deaths caused by the blue-ringed octopus — two in Australia and one in Singapore, according to the Australian Institute of Marine Science.

While this potent toxin may lead to an agonizing death in as little as 20 minutes or as long as 24 hours, some people have lived to tell the tale. The outcomes are "actually wildly variable," Grasse said. "Some instances where humans have had confirmed bites from blue ring octopuses result in absolutely nothing."

In one case from 2006, a 4-year-old boy was bitten by a blue-ringed octopus in Australia. Within 10 minutes of exposure, the boy had vomited three times, reported having blurry vision and couldn't stand on his own. An ambulance rushed him to the emergency department, where he was put on a ventilator to help him breathe for a total of 17 hours. But 28 hours after the initial bite, he was discharged with no long-term complications. Grasse confirmed that seeking medical help and use of a ventilator is the best route to go in this case.

This small but mighty creature can certainly take care of itself. "It's a widely utilized advantage that they have, and they deploy in various ways," Grasse said.

About 66 million years ago — perhaps on a downright unlucky day in May — an asteroid smashed into our planet.

The fallout was immediate and severe. Evidence shows that about 70% of species went extinct in a geological instant, and not just those famous dinosaurs that once stalked the land. Masters of the Mesozoic oceans were also wiped out, from mosasaurs — a group of aquatic reptiles topping the food chain — to exquisitely shelled squid relatives known as ammonites.

Even groups that weathered the catastrophe, such as mammals, fishes and flowering plants, suffered severe population declines and species loss. Invertebrate life in the oceans didn't fare much better.

But bubbling away on the seafloor was a stolid group of animals that has left a fantastic fossil record and continues to thrive today: bivalves — clams, cockles, mussels, oysters and more.

What happened to these creatures during the extinction event and how they rebounded tells an important story, both about the past and the future of biodiversity.

Surprising discoveries on the seafloor

Marine bivalves lost around three-quarters of their species during this mass extinction, which marked the end of the Cretaceous Period. My colleagues and I — each of us paleobiologists studying biodiversity — expected that losing so many species would have severely cut down the variety of roles that bivalves play within their environments, what we call their "modes of life."

But, as we explain in a study published in the journal Sciences Advances, that wasn't the case. In assessing the fossils of thousands of bivalve species, we found that at least one species from nearly all their modes of life, no matter how rare or specialized, squeaked through the extinction event.

Statistically, that shouldn't have happened. Kill 70% of bivalve species, even at random, and some modes of life should disappear.

Related: The 5 mass extinction events that shaped the history of Earth — and the 6th that's happening now

Most bivalves happily burrow into the sand and mud, feeding on phytoplankton they strain from the water. But others have adopted chemosymbionts and photosymbionts — bacteria and algae that produce nutrients for the bivalves from chemicals or sunlight in exchange for housing. A few have even become carnivorous. Some groups, including the oysters, can lay down a tough cement that hardens underwater, and mussels hold onto rocks by spinning silken threads.

We thought surely these more specialized modes of life would have been snuffed out by the effects of the asteroid's impact, including dust and debris likely blocking sunlight and disrupting a huge part of the bivalves' food chain: photosynthetic algae and bacteria. Instead, most persisted, although biodiversity was forever scrambled as a new ecological landscape emerged. Species that were once dominant struggled, while evolutionary newcomers rose in their place.

The reasons some species survived and others didn't leave many questions to explore. Those that filtered phytoplankton from the water column suffered some of the highest species losses, but so did species that fed on organic scraps and didn't rely as much on the Sun's energy. Narrow geographic distributions and different metabolisms may have contributed to these extinction patterns.

Biodiversity bounces back

Life rebounded from each of the Big Five mass extinctions throughout Earth's history, eventually punching through past diversity highs. The rich fossil record and spectacular ecological diversity of bivalves gives us a terrific opportunity to study these rebounds to understand how ecosystems and global biodiversity rebuild in the wake of extinctions.

The extinction caused by the asteroid strike knocked down some thriving modes of life and opened the door for others to dominate the new landscape.

While many people lament the loss of the dinosaurs, we malacologists miss the rudists.

These bizarrely shaped bivalves resembled giant ice cream cones, sometimes reaching more than 3 feet (1 meter) in size, and they dominated the shallow, tropical Mesozoic seas as massive aggregations of contorted individuals, similar to today's coral reefs. At least a few harbored photosymbiotic algae, which provided them with nutrients and spurred their growth, much like modern corals.

Today, giant clams (Tridacna) and their relatives fill parts of these unique photosymbiotic lifestyles once occupied by the rudists, but they lack the rudists' astonishing species diversity.

Mass extinctions clearly upend the status quo. Now, our ocean floors are dominated by clams burrowed into sand and mud, the quahogs, cockles and their relatives — a scene far different from that of the seafloor 66 million years ago.

New winners in a scrambled ecosystem

Ecological traits alone didn't fully predict extinction patterns, nor do they entirely explain the rebound. We also see that simply surviving a mass extinction didn't necessarily provide a leg up as species diversified within their old and sometimes new modes of life — and few of those new modes dominate the ecological landscape today.

Like the rudists, trigoniid bivalves had lots of different species prior to the extinction event. These highly ornamented clams built parts of their shells with a super strong biomaterial called nacre — think iridescent pearls — and had fractally interlocking hinges holding their two valves together.

But despite surviving the extinction, which should have placed them in a prime position to accumulate species again, their diversification sputtered. Other types of bivalves that made a living in the same way proliferated instead, relegating this once mighty and global group to a handful of species now found only off the coast of Australia.

Lessons for today's oceans

These unexpected patterns of extinction and survival may offer lessons for the future.

The fossil record shows us that biodiversity has definite breaking points, usually during a perfect storm of climatic and environmental upheaval. It's not just that species are lost, but the ecological landscape is overturned.

Many scientists believe the current biodiversity crisis may cascade into a sixth mass extinction, this one driven by human activities that are changing ecosystems and the global climate. Corals, whose reefs are home to nearly a quarter of known marine species, have faced mass bleaching events as warming ocean water puts their future at risk. Acidification as the oceans absorb more carbon dioxide can also weaken the shells of organisms crucial to the ocean food web.

Findings like ours suggest that, in the future, the rebound from extinction events will likely result in very different mixes of species and their modes of life in the oceans. And the result may not align with human needs if species providing the bulk of ecosystem services are driven genetically or functionally extinct.

The global oceans and their inhabitants are complex, and, as our team's latest research shows, it is difficult to predict the trajectory of biodiversity as it rebounds — even when extinction pressures are reduced.

Billions of people depend on the ocean for food. As the history recorded by the world's bivalves shows, the upending of the pecking order — the number of species in each mode of life — won't necessarily settle into an arrangement that can feed as many people the next time around.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

An elusive species of deep-sea squid has been seen alive for the first time off Antarctica, National Geographic has announced.

Researchers filmed the Antarctic gonate squid (Gonatus antarcticus) drifting through the black waters of the ocean's midnight zone, 7,060 feet (2,152 meters) below the surface, on Dec. 25, 2024.

As first reported by National Geographic, researchers spotted the 3-foot-long (0.9 m) blood-red creature using a remotely operated vehicle (ROV), which had been deployed from the Schmidt Ocean Institute’s research vessel, the R/V Falkor (too). They sent the footage to Kat Bolstad, head of the Lab for Cephalopod Ecology and Systematics at Auckland University of Technology in New Zealand, who confirmed it was an Antarctic gonate squid.

"This is, to the best of my knowledge, the first live footage of this animal worldwide," Bolstad told National Geographic.

Related: Elusive colossal squid finally caught on camera 100 years after discovery in world 1st footage — and it's tiny

Scientists have known about the Antarctic gonate squid for more than 100 years, but they have previously only seen dead specimens caught in fishing nets or beaks that had been preserved in the stomachs of other animals. This is the first time scientists have observed the squid alive and in its natural habitat.

The creature was in the bathypelagic or midnight zone, 3,300 to 13,100 feet (1,000 to 4,000 m) below the ocean's surface. No sunlight can penetrate that far into the ocean, so the midnight zone's only light comes from animals that can illuminate themselves with bioluminescence, according to the National Oceanic and Atmospheric Administration (NOAA).

The squid released a cloud of greenish ink when the ROV approached, potentially startled by the presence of a large, bright vehicle in its environment. The researchers followed the animal for a few minutes, using the ROV's lasers to measure its size, before the squid shot away into the darkness, National Geographic reported.

While researchers couldn't determine the sex or age of the animal, Bolstad confirmed it was an Antarctic gonate squid by observing the presence of a single, large hook on the ends of its two longer tentacles.

"The impressive tentacle hooks are probably used for grasping and subduing prey during ambush predation," Alex Hayward, a senior lecturer in ecology and conservation at the University of Exeter in England who was not involved in the expedition, told National Geographic.

The scaly-foot snail, or volcano snail, possesses something unique among gastropods: a coat of protective armor covering its foot, made from hundreds of overlapping iron-infused scales. It fortifies these scales with minerals absorbed from the hot liquid spewed by hydrothermal vents and black smoker chimneys at the bottom of the Indian Ocean, where water can reach temperatures of 752 degrees Fahrenheit (400 degrees Celsius).

Related: Elusive colossal squid finally caught on camera 100 years after discovery in world 1st footage

Within the snail's scales, sulfur reacts with iron ions to form iron sulfide nanoparticles. Further toughening the snail's defenses is an outer layer of iron sulfide in its shell, making it the only known multicellular animal to strengthen its skeleton with iron. When the National Museum of Wales acquired a pair of specimens in 2015, curators were told to avoid using any water in the preservative solution, because otherwise the snails would start to rust.

Underneath all that armor, the scaly-foot snail has a big heart — the largest in the Animal Kingdom relative to the animal's size — making up about 4% of the volume of its entire body. In waters where oxygen levels are low, that enormous heart also supplies oxygen to the symbiotic bacteria that live in the snail's esophageal gland and act as a built-in food factory. The snails, whose shells measure about 2 inches (5 centimeters) in length on average, are sometimes called "sea pangolins" for their resemblance to the armor-plated land mammal.

Individuals have both male and female sex organs. They creep along the ocean bottom at depths of approximately 1.7 miles (2,780 meters), and are known from just three hydrothermal vent fields to the east of Mauritius, an island off the southeastern coast of Africa.

While the snails' potential habitat adds up to around 0.1 square miles (0.3 square kilometers), the range where they are currently found covers just 0.008 square miles (0.02 sq km). But even this tiny sliver of the deep ocean is becoming unsafe for the snails, due to human activity.

In 2019, the International Union for Conservation of Nature (IUCN) added scaly-foot snails to its Red List of life at risk of extinction. The snails became the first animal to be listed as "endangered" due to threats to two of its three habitat locations from deep sea mining.

In a world first, scientists have filmed a rare carnivorous snail laying an egg from a "genital pore" in its neck.

The footage answers long-standing questions about how the mysterious mollusks — known as the Mount Augustus snail (Powelliphanta augusta) — reproduce.

"It's remarkable that in all the time we've spent caring for the snails, this is the first time we've seen one lay an egg," Lisa Flanagan, a New Zealand Department of Conservation (DOC) ranger who captured the footage, said in a statement. "We caught the action when we were weighing the snail. We turned it over to be weighed and saw the egg just starting to emerge from the snail."

In the video, a single pearly white egg oozes out of the snail's slimy neck folds, from an opening known as a genital pore.

There are at least 20 species and 59 sub-species of Powelliphanta snails, and they are among the largest snails in the world, according to the DOC. Powelliphanta snails are nocturnal and rarely come out during the day, except when it is particularly rainy. Therefore, they are not often very rarely spotted by humans.

They are also among New Zealand's most threatened invertebrate species due to predation and habitat loss.

According to the DOC , P. augusta, only found on the Buller Plateau on New Zealand's West Coast, are threatened by extinction due to open-cast coal mining in their native range.

Because of their shrinking population and nocturnal behavior, very little is known about these creatures' life cycle and behavior. Therefore, wildlife officials have been studying a population in captivity for nearly 20 years.

"DOC has been managing this captive population in chilled containers in Hokitika since 2006, when work began to mine the majority of their habitat on the West Coast of the South Island," the DOC representatives said in a Facebook post. "Very little was known about the species before they were taken into captivity."

Like many snails, Powelliphanta are hermaphrodites, meaning they have both male and female reproductive organs. P. augusta are long-lived and slow to mature, only reaching sexual maturity at around 8 years old — which is very old for a snail. Mature snails usually lay around five eggs a year, which can take more than a year to hatch.

"Some of our captive snails are between 25 and 30 years old — in this they're polar opposites to the pest garden snail we introduced to New Zealand which is like a weed, with thousands of offspring each year and a short life," Kath Walker, DOC senior science advisor, said in the statement.

While the snails' hard shells help to protect them from predation and harsh conditions, they also make it difficult to get sperm from one snail into another. "Powelliphanta have solved this by having an opening (a genital pore) on the right side of their body just below their head so that the snail only needs to peek out of its shell to do the business," Walker said.

"It extends its penis out of this pore and into its mate's pore, and its mate does the same, simultaneously exchanging sperm, which they can store until they each fertilise the sperm they've received to create eggs," Walker said.

She added that, because they have both male and female reproductive organs, the snails can also self-fertilize.

Laying eggs through a genital pore is common among snail species, although some species, such as Littorina saxatilis in the U.K., give birth to live young. But Powelliphanta species are unusual because they only lay one egg at a time, rather than the big eggy clusters produced by many other more common snail species, according to the Carnegie Museum of Natural History.

To save these exotic snails, the DOC has established new populations in the wild by introducing them into new and rehabilitated habitats. However, they will continue to manage populations in captivity too until they are confident that the species is surviving well in the wild.

"The captive management of Powelliphanta augusta has not only saved the species from extinction, but it's allowed us to learn more about the lives of these incredible creatures found nowhere else in the world," according to the statement.

Cuttlefish may "wave" at each other with their tentacles to communicate, new research suggests.. But the study, which has not yet been peer-reviewed, didn't determine what messages the arm waving conveyed.

Cuttlefish communication is complex, sometimes combining skin colors and patterns with changes in body posture. Cuttlefish even release ink during courtship displays, creating multifaceted signals. They use tentacle motions for communication as well — for example, when males confront other males, they may flare or extend their "arms" to show aggression.

In the new study, the research team studied arm waving — when cuttlefish lift their tentacles to possibly initiate interactions with other cuttlefish doing the same. The researchers focused on the common cuttlefish (Sepia officinalis) and the dwarf cuttlefish (Sepia bandensis), after noticing these species seemed to perform specific arm movements in a consistent way.

The researchers identified four "arm wave signs" — repeated sequences of arm undulations that could be combined to create particular patterns: the "up" sign, "side" sign, "roll" sign and "crown" sign.

The research team recorded videos of cuttlefish performing the movements and played them back. The cuttlefish often placed themselves in front of the videos and waved back at themselves, said Sophie Cohen-Bodénès, a neuroscientist at PSL University in Paris and co-author of the new paper. They repeated the movements back at themselves significantly more when the video was in an upright configuration, as opposed to flipped upside down, suggesting the wave signs have significance that cuttlefish interpret when oriented correctly.

The researchers also found that the arm movements produced vibrational waves in the water. "When they don't see each other — for example, if there is a big rock in the tank — they would still do the signs," Cohen-Bodénès told Live Science. "It produces vibrations in the water, and that could be perceived."

To test the role of these vibrations, the researchers recorded the vibrational trace of the waving behavior with a hydrophone, an instrument that detects sound waves in the water. Then, they created versions of the vibrational signal that were reversed and scrambled, and played both these versions and the original recording in the water. They found that the cuttlefish responded only to the original vibrational recordings — suggesting the order of the vibrations could have a specific meaning.

"It was very impressive, because they would come to the hydrophone, and just in front of the hydrophone, they would display back the signs," Cohen-Bodénès said.

Yet defining a behavior as communication is complex, said Trevor Wardill, a biologist at the University of Minnesota who was not involved in the new study. One issue is the interpretation of an animal responding to recordings of itself as communication, since that response may be more similar to how animals respond to themselves in a mirror, Wardill told Live Science. But when kept in tanks, cuttlefish do sometimes wave their arms when caretakers pass by, possibly to get caretakers’ attention and be fed, Wardill hypothesized.

"I would not be surprised if there's actually communication; I don't think that's out of the realm of possibility, because they are a social species," Wardill said. The next step is to get the evidence to show very clearly what's going on and to link the sender of a signal and the receiver responding to that signal, Wardill added.

The research team said the experiments lend support to their hypothesis that cuttlefish arm waving is a communication signal that combines visual cues and vibrational waves, although they noted that further research is needed.

The researchers hope machine learning tools that are used to analyze sequences of cephalopod skin patterns can decipher what the arm movements mean in different contexts. They are also interested in developing a cuttlefish-like underwater robot that could display these signals and produce vibrations, to see how cuttlefish might respond to it.

"Our analyses are consistent, but it opens a box for further analysis, to completely decipher the meaning of the signs," Cohen-Bodénès said.

The elusive colossal squid has finally been caught on camera, an entire century after it was first discovered.

A team of scientists aboard the Schmidt Ocean Institute's research vessel Falkor filmed a not-so-colossal juvenile measuring 11.8 inches (30 centimeters) long as it swam through the ocean near the South Sandwich Islands at a depth of around 1,968 feet (600 meters).

The video, which was captured on March 9 in the South Atlantic Ocean by a remotely operated vehicle (ROV) named SuBastian, shows the translucent baby squid gently swimming through the abyss of the deep ocean, with its tiny tentacles dangling behind it.

"It's exciting to see the first in situ footage of a juvenile colossal and humbling to think that they have no idea that humans exist," Kat Bolstad, a squid researcher at the the Auckland University of Technology in New Zealand, who was an independent scientific expert consulted to verify the footage, said in a statement. "For 100 years, we have mainly encountered them as prey remains in whale and seabird stomachs and as predators of harvested toothfish."

Colossal squid (Mesonychoteuthis hamiltoni) are bigger than even the famous giant squid (Architeuthis dux). They are considered the largest invertebrates on the planet, measuring up to 46 feet (14 m) long — as long as a semitrailer — and weighing as much as 1,100 pounds (500 kilograms). They have the largest eyes of any known animal, which can measure up to 11 inches (27 cm) across — about the size of a soccer ball.

These bizarre creatures live deep beneath the Antarctic waters of the Southern Ocean. They live deeper and deeper with age, with the youngest and smallest squid being found down to about 1,640 feet (500 m), adolescents living between 1,600 and 6,600 feet (500 to 2,000 m), and fully grown adults living even deeper.

This year marks 100 years since the colossal squid was formally identified and named, but in the century since, very few have ever been seen. The species was first discovered after two of its arms were found in the stomach of a sperm whale during the winter of 1924-1925.

The new video is the first-ever live observation of this species in its natural habitat. Dying adult colossal squid have been filmed by fishermen, and the first complete specimen was captured in 2007 by a fishing vessel near Antarctica. Most of what we know about this species and its lifestyle comes from beaks found in sperm whale stomachs. Only 12 complete colossal squid specimens had ever been found as of 2015, and about half of those were juveniles.

The scientists on the previous Falkor expedition in January also filmed the first-ever confirmed footage of the glacial glass squid (Galiteuthis glacialis), which had also never been observed in its natural habitat before now.

"The first sighting of two different squids on back-to-back expeditions is remarkable and shows how little we have seen of the magnificent inhabitants of the Southern Ocean," Jyotika Virmani, Schmidt Ocean Institute's executive director, said in the statement. "These unforgettable moments continue to remind us that the ocean is brimming with mysteries yet to be solved."

Hypnotizing footage reveals a never-before-seen swimming sea slug that eats using a large jelly-like hood and glows to defend itself from predators.

Living at depths of between 3,300 and 13,100 feet, (1,000 to 4,000 meters), the mystery mollusc (Bathydevius caudactylus) is the first nudibranch species found living in the deep water column. Researchers first captured footage of the animal in February 2000 using a remotely operated vehicle (ROV) off the Monterey Bay coast. They spent the next 20 years learning more and gathering enough information to publish the most comprehensive description of a deep-sea animal to date.

Nudibranchs, or sea slugs, usually live and feed on the seafloor, but the newly described bioluminescent species swims through the ocean's midnight zone, deep below the surface. The newfound species is 5.6 inches (14 centimeters) long with an enormous gelatinous hood, a fringed tail, colorful organs visible through its translucent body, and a foot, like a snail.

At first, the researchers couldn't figure out what this strange animal was, so they nicknamed it the "mystery mollusk." When they got it back to the lab, anatomical and genetic tests confirmed it was a nudibranch.

It is so distinct from other known nudibranchs that the researchers created a new family: Bathydevius, which refers to the way this "devious" animal fooled researchers with its unique features. It was given its species name caudactylus thanks to the finger-like projections, or dactyls, on its tail.

"We were extremely surprised to find that Bathydevius is a nudibranch, partly because it doesn't look like the others, but also because this is such an unusual habitat for a nudibranch," Bruce Robison, senior scientist at Monterey Bay Aquarium Research Institute (MBARI), told Live Science via email. Robison led the efforts to describe the mystery mollusk.

"Most nudibranchs live on the seafloor in shallow water and feed on attached prey," he said. "Moving into the deep water column and feeding on free-swimming, fast-moving prey is a real challenge."

Researchers at MBARI published everything they know about this bizarre animal — through more than 150 sightings across a 20-year time period — on Nov. 12 in the journal Deep-Sea Research Part I.

Related: 'Mind-blowing' deep sea expedition uncovers more than 100 new species and a gigantic underwater mountain

The sea slug's translucent body likely protects it from being seen by predators, Robison said.

The scientists believe the mystery mollusk uses its hood like a Venus fly trap to catch crustaceans to eat. The hunting technique is used by several other sea creatures. "Several unrelated animals, including the large jellyfish Deepstaria and fragile comb jellies, entrap their prey in what looks like a living grocery bag," co-author Steven Haddock, senior scientist at MBARI, told Live Science via email. "It's like throwing a rope net to stop a charging lion."

Although the mystery mollusk feeds in a similar way to the lion's mane nudibranch (Melibe leonina) and the veiled nudibranch (Tethys fimbria), these species are only distantly related, so this is a case of convergent evolution.

"Given the genetic separation from all other nudibranchs and its radically divergent body plan, it seems clear that this is a successful evolutionary experiment," Robison said.

When under threat, the mystery mollusk uses bioluminescence to distract its predators. In one instance, researchers saw it detach a bioluminescent limb as a decoy, similar to a lizard dropping its tail.

The mystery mollusk is known to live in the northeastern Pacific Ocean, from Oregon to Southern California. However, experts believe its distribution could be more widespread, as NOAA researchers have observed a similar-looking animal in the Mariana Trench — the deepest part of the ocean, located in the Western Pacific.

The experts still want to solve the puzzle of how this animal feeds. "We know what it eats but we can't figure out how this slow-moving sea slug can capture those very fast shrimp," Robison said.

Cameras at the bottom of the Tonga Trench in the South Pacific have captured rare footage of a bigfin squid with spindly arms that stretch several feet long, a new video shows.

Bigfin squid (Magnapinna) are an extremely elusive type of cephalopod — a group that also includes octopus and cuttlefish — with only around a dozen sightings on record. They are the deepest-dwelling species of squid known to science, surviving at depths of more than 20,000 feet (6,100 meters), according to the Ocean Conservancy.

The new footage is from 10,800 feet (3,300 m) beneath the ocean surface. Researchers spotted the squid by chance while exploring the trench, and they say it was a lucky encounter.

"We always hope to see this type of animal," Alan Jamieson, a professor and deep-sea scientist at the University of Western Australia who collected the footage, told Live Science in an email. "[Bigfin squid] are not something you would actively go looking for, they are a species that relies on us coming across them by accident," Jamieson said.

Most documented bigfin squid sightings are "serendipitous filming from oil and gas activities," Jamieson said.

Related: Rare video shows elusive deep-sea squid cradling her gigantic, translucent eggs

The squid in the new video was probably feeding or attempting to feed, he said. The footage shows the otherworldly animal walking slowly along the seafloor before suddenly stopping and pulsing the big fins attached to its body. Although it looks like the squid is tugging on something off camera, it's likely just trying to pull its sticky arms off the seafloor, Jamieson said.

Researchers estimate that the squid's body is 8 to 12 inches (20 to 30 centimeters) long. Its arms stretched several times that length and looked "extremely disproportionate," Jamieson said. Scientists think bigfin squid can grow up to 26 feet (8 m) long, including the arms.

Why bigfin squid evolved such long, spindly arms remains a mystery, Jamieson said, but it's probably related to feeding. Bigfin squid are the only squid known to live at hadal depths — between 19,700 and 36,000 feet (6,000 to 11,000 m) deep — where food is scarce and mostly comes in the form of particles falling from above.

To solve the mystery, scientists first need to know more about the squid themselves. "The trick is to keep filming everything else that's going on and eventually, if you are lucky, one will grace you with its presence," Jamieson said.

Name: Pacific geoduck (Panopea generosa)

Where it lives: In the Pacific Ocean, off the west coast of North America (Alaska to Baja California, Mexico)

What it eats: Phytoplankton, pelagic crustaceans and fish larvae

Why it's awesome: Pacific geoducks are large, saltwater clams that can live longer than 165 years. These phallic-looking sea creatures have very long necks called siphons and are considered a culinary delicacy.

The name geoduck — pronounced "gooey duck" — is thought to come from the Native American Nisqually word "gweduc," which means "dig deep." They are the largest burrowing clams in the world and live in the ocean floor to a depth of 3 feet (1 meter).

Geoducks are bivalves, which means their bodies are compressed between a shell that consists of two hinged parts. They have a foot, which helps them dig into the sediment and anchor to the ground. To eat, the mollusk sucks in seawater, filters it for plankton and nutrients, and squirts out the excess through its siphon. This appendage has two openings at the end — one for taking in oxygen and phytoplankton, and one for releasing excess water.

Related: 10 phallic flora and fauna that look just like penises

Although a geoduck’s shell usually measures 6 to 8 inches (15 to 20 centimeters) in length, the siphon can grow longer than 3 feet. In their first three to five years, geoducks grow up to 1.5 pounds (0.7 kilogram). On average, geoducks weigh around 2.5 pounds (1.1 kg), but they can reach 9 pounds (4 kg).

Adult geoducks have separate sexes, and they reach sexual maturity at around 3 years old. Male geoducks are capable of reproducing for more than 100 years. Females have very large ovaries that contain many millions of eggs, and they release between 1 million and 2 million eggs per spawn.

Whereas other clams move to avoid predators, geoducks react by retracting their siphons. They are preyed upon by crabs, dogfish, sea otters and starfish. Geoducks are eaten around the world and are served cooked or raw in sushi or sashimi. They are harvested in the wild as well as farmed, particularly in Washington state. These clams are sometimes purported to have aphrodisiac properties, likely because of their shape — but there is no scientific evidence to support this claim.

Scientists in China may have identified a newfound species of vampire squid — only the second known species in the world. 

Vampire squid (Vampyroteuthis infernalis) reach lengths of about 1 foot (0.3 meters). Despite their menacing appearance and name, they are deep-sea scavengers and are unlikely to harm anything aside from small invertebrates and in fact usually gravitate toward feces and dead animals.

The species has been found in temperate and tropical ocean environments in many areas of the world.

The only officially recognized species was described in 1903 following a deep-sea expedition led by German marine biologist Carl Chun. A number of additional species were later described but eventually turned out to be members of the same species. 

These supposed newfound species were juvenile forms of V. infernalis, which had very different physical characteristics — the squid grows a second set of fins closer to its head as it matures and its original fins disappear.

Related: Rare video shows elusive deep-sea squid cradling her gigantic, translucent eggs

"Ten synonymous species that had previously been described showed some morphological differences in their various life stages," study lead author Dajun Qiu, a marine biologist at the South China Sea Institute of Oceanology, told Live Science.

Now, in a new study that appeared on May 2 in the preprint journal BioRxiv, researchers have described a second species of vampire squid found in the South China Sea, near Hainan island, China, in 2016, which they named V. pseudoinfernalis. It was found around 2,600 to 3,300 feet (800 to 1,000 meters) below the sea surface, in the so-called twilight zone, where little light from the surface penetrates.

This newly identified species displays some unique characteristics that distinguish it from V. infernalis. For example, the position of two photophores — light-producing organs — located between its fins and tail are different. In V. infernalis, they are located a third of the way between the fins and the end of the body, while in V. pseudoinfernalis they are located roughly halfway between these points. V. pseudoinfernalis also has a pointed tail while V. infernalis does not have one at all. The newfound species also has a beak with a longer wing on its lower jaw. 

In photographs of the preserved specimen, it looks like a black, gelatinous blob — but in its deep-sea environment it likely shares the billowing, cloak-like form of its cousin.

Genetic analysis further suggests that V. pseudoinfernalis is a distinct species, Qiu noted.

"We will analyze more specimens to ensure that observed morphological differences are consistent in the future," Qiu said. It seems likely that its diet is similar to its better-known relative, but research is ongoing, he said.

While the order Vampyromorphida contains only V. infernalis and the proposed V. pseudoinfernalis, numerous extinct relatives exist in the fossil record. A newfound species, unearthed in Luxembourg in 2022, was preserved with fish clasped in its tentacles, according to a 2024 paper.

Scientists have captured stunning video of a female deep-sea squid cradling unusually large eggs in her tentacles. The footage, taken by the team via a remotely operated vehicle (ROV) off Mexico's coast, reveals that the mother squid was carrying about 40 eggs, each around twice as large as those of previously encountered squid. 

The new video reveals additional details about the life cycle of deep-dwelling squid. These animals are rarely seen alive at depth and little is known about how they reproduce in a dark and cold environment, where oxygen and food is limited.

"The deep sea is the largest living space on Earth and there is a lot left to be discovered," Steven Haddock, a senior scientist and expedition leader at the Monterey Bay Aquarium Research Institute (MBARI), said in a statement. "Our unexpected encounter with a squid brooding giant eggs caught the attention of everyone in the ship’s control room." The findings were published in May in the journal Ecology. 

Seeing a deep-sea squid brooding, or protecting eggs after laying them, is especially rare. Most squids leave their eggs drifting in the water column or attached to the seafloor, according to the statement. Brooding is extremely arduous for female squid. This process often leads to the mothers dying after the eggs hatch, Henk-Jan Hoving, a deep-sea biologist at the GEOMAR Helmholtz Centre for Ocean Research in Germany and lead author of the paper, said in the statement.

The researchers encountered the brooding squid in 2015 during an expedition to the Gulf of California to study animals that live in an extremely oxygen-poor environment. As the scientists launched ROVs into the deep basin, they spotted the mother, at around 8,418 feet (2,566 meters) deep. The species identity of this squid has never been described, but likely belongs to the family Gonatidae which is common in the Pacific Ocean.

While capturing video of a squid brooding is rare, it isn't unprecedented. MBARI scientists first spotted a female squid, of the species Gonatus onyx, — also from the family Gonatidae — brooding in Monterey Bay in 2002. In 2005, they filmed a brooding deep-sea squid (Bathyteuthis berryi) from a different family in the same geographic area. Over 37 years of exploration, MBARI scientists have observed 17 squid mothers cradling their eggs.

The mother squid they encountered in 2015 had far fewer eggs than the brooding squid in 2002, which carried 3,000 small eggs. Having many small eggs can be advantageous when food is limited and predators are abundant. Meanwhile, larger eggs are better for a less-threatening, stable environment, the researchers wrote in the study.

The squid the scientists encountered in the Gulf of California was about 3,000 feet (900 m) deeper than the one seen in Monterey two decades ago. The move into deeper territory with extremely low oxygen levels may be a strategic choice made to avoid predators such as sharks and seals, the researchers wrote in the study.

"This remarkable sighting underscores the diversity of ways that animals adapt to the unique challenges of living in the deep," Haddock said.

One of the world's most elusive squid species put on a blinding bioluminescent display as it attacked an underwater camera in the deep sea, exceptionally rare new footage reveals.

Researchers from the Minderoo Foundation and the University of Western Australia (UWA) Deep Sea Research Center captured the rare encounter, which occurred around 3,281 feet (1,000 meters) below the Pacific Ocean's surface, using a free-falling baited camera dropped into the sea near the Samoan Passage — an area of deep water flow north of Samoa. 

The team was on a research cruise documenting the diversity of the deepest part of the ocean — the hadal zone — when they spotted the rare creature.

The animal in the video is a Dana octopus squid (Taningia danae), a member of the family Octopoteuthidae that feeds on pelagic fish, crustaceans and other squid species. 

Squid species within the Octopoteuthidae family have eight arms which is why they are called octopus squid. As juveniles they have two long, trailing tentacles in addition to their arms, but these are lost as the squid matures.

Members of this species are known for their colossal size. The longest individual ever reported was a 7.5-foot-long (2.3 m) female, according to a 2003 study. The individual in the new video is around 2.5 feet (75 centimeters) long, according to a statement from UWA.

In the footage, the squid suddenly appears from the darkness and darts toward the camera, engulfing it with its arms before making a quick getaway. Moments before latching onto the camera, the squid shows off a pair of bright, light-emitting organs, known as photophores, at the tips of two of its arms.

This species' photophores — which emit bursts of light as a result of a chemical reaction — are the largest of their kind in the animal kingdom, researchers wrote in the statement. But scientists have rarely seen the squids' biological lights used in action. 

"As we were reviewing the footage, we realized we had captured something very rare," Heather Stewart, a marine geologist and affiliate researcher at UWA, said in the statement. "I think we were very lucky to have witnessed this."

Related: Black-eyed squid dragging thousands of eggs like a cape captured in video off Costa Rica

Researchers believe the squids' photophores help them stun prey in the dark waters of the deep sea and possibly communicate with other individuals of the same species. These squid can change the pattern of flashes by controlling the eyelid-like membranes that cover their light-producing organs, according to a 2017 study.

In the video, the squid "descended on our camera assuming it was prey, and tried to startle it with its huge bioluminescent headlights," Stewart said.

Overall, researchers know very little about this species' behavior because T. danae are rarely seen alive. 

"Many records of this species are from strandings, accidental bycatch or from the stomach contents of whales," Alan Jamieson, director of UWA's Deep Sea Research Centre, said in the statement. 

T. danae were only spotted alive for the first time around 19 years ago, by researchers using a similar camera system, according to a study published in 2007. And these squid have been seen alive only a handful of times since.

"The rarity of live observations of these amazing animals makes every encounter valuable in gathering information on geographic locations, depth, and behavior," Jamieson said in the statement.

Name: Blue dragon (Glaucus atlanticus)

Where it lives: Tropical and subtropical waters throughout the Atlantic, Pacific and Indian oceans 

What it eats: Portuguese men o'war and other venomous animals

Why it's awesome: This tiny sea creature, which grows up to 1.2 inches (3 centimeters) long, is a type of nudibranch, or sea slug. Also known as a sea swallow or blue angel, it has three sets of ornate "wings" — called cerata — that makes it look a bit like a Pokémon.

Its beautiful and otherworldly appearance is down to its lifestyle. The blue dragon lives on the surface of the ocean, bobbing along using an air bubble in its stomach and the water's surface tension to keep it afloat. 

It floats upside down for better camouflage: The sea slug's bright blue coloring blends in with the surface of the water from above while its silvery-gray back looks like the sky from below.

The blue dragon feasts on venomous creatures including Portuguese men o'war (Physalia physalis), by-the-wind-sailors (Velella velella) and violet sea snails (Janthina janthina). 

Related: Green-banded broodsac — the brain-hijacking parasite that creates disco zombie snails

The tiny creature floats on the underside of the water to approach its prey and uses a mucus layer to prevent being stung when it takes a bite with its serrated teeth and hard discs in its stomach, which provide an extra layer of defense against the sting. 

The sea slug can't create its own toxins, but when it eats venomous prey it stores the stinging cells in its cerata and can release them all at once in self defense if it feels threatened. This species drifts with the current, which means they can wash up on the beach — sometimes with thousands stranding together. But swimmers and beachgoers are warned to keep their distance because the tiny critter can pack a punch. 

"That's what makes them so dangerous, since they can release the stinging cells all at one time," Jace Tunnell, director of community engagement at the Harte Research Institute for Gulf of Mexico Studies, told the BBC. "It can be three times the intensity as a man-o-war due to that." 

Blue dragon mating is also pretty interesting. As hermaphrodites, each individual will have both male and female reproductive organs at the same time. After mating, they lay a string of up to 16 eggs which will hatch in just a few days. 

A deep-sea squid has been filmed gliding through inky waters with thousands of eggs suspended from its arms.

Researchers spotted the black-eyed squid (Gonatus onyx) — one of the few squids known to brood their eggs — off the coast of Costa Rica in December. Mesmerizing footage shows the squid trailing its cargo of eggs like a long gown and flapping the fins protruding from its head to move through the water.

"The large egg mass is suspended from hooks on the squid's arms, and while carrying it for several months, the cephalopod will go without feeding," representatives of the Schmidt Ocean Institute, which organized the expedition, wrote in a post on Instagram. 

Marine biologists had long assumed that black-eyed squid and other squids lay their eggs in clusters on the seafloor, leaving them to develop and hatch independently. However, in 2001, Brad Seibel, a postdoctoral fellow at the Monterey Bay Aquarium Research Institute (MBARI), turned this assumption on its head. Seibal observed a black-eyed squid brooding an egg sack in Monterey Canyon, off the coast of California, through the lens of a remotely operated submersible.

Related: Watch elusive, sucker-less squid in rare footage captured off the Galapagos 

"I just remember jumping out of my seat," Seibel, now a professor of biological oceanography at the University of South Florida, told Science Friday in 2016.

In a 2005 study, Seibel and colleagues described the brooding behavior of G. onyx females, which carry up to 3,000 eggs through open water until the young hatch and swim away. The squid use their arms to pump fresh water through the egg mass, which may help keep them supplied with oxygen. 

Black-eyed squid are among the most abundant cephalopods in the Pacific and Atlantic oceans, according to the study. In the North Pacific Ocean, the species is typically found at depths above 6,200 feet (1,900 meters).

These squid are neutrally buoyant, meaning they don't require any effort to float or swim, but "brooding squid cannot swim very quickly, and may be easy prey for deep-diving marine mammals," according to the Instagram post.

An Australian teenager had a lucky escape after being bitten by one of the world's most toxic animals, a blue-ringed octopus, after accidentally picking up the deadly cephalopod hiding in a shell. But this was not the only close call — he almost passed the tiny creature to a toddler, which could have been disastrous.

Blue-ringed octopuses are a group comprising four species: the greater blue-ringed octopus (Hapalochlaena lunulata), the southern blue-ringed octopus (Hapalochlaena maculosa), the blue-lined octopus (Hapalochlaena fasciata) and the common blue-ringed octopus (Hapalochlaena nierstraszi). These octopuses, which are all small enough to fit in the palm of your hand, contain tetrodotoxin — a powerful neurotoxin with no known antidote that can paralyze and kill humans within minutes, even in small doses.

Eighteen-year-old Jacob Eggington was swimming off Shoalwater Beach near Perth when he scooped up a shell, which, unbeknownst to him, contained an unidentified species of blue-ringed octopus, local news site PerthNow reported. Egginton placed the shell in his pocket and took it ashore to show his family. When he took it out of his pocket to show his infant niece, he spotted the blue-ringed octopus and dropped it to the floor.

"As soon as he saw the octopus, he yelled really loudly," Eggington's brother Joshua told 7NEWS Perth. "Just a few seconds later and the toddler would have been holding it."

After examining his leg, Egginton found a small painless bite and started to feel unwell. He was stretchered off the beach and taken to hospital, where he was treated for more than six hours. He was later released and is expected to make a full recovery. 

Related: Tiny, highly venomous jellyfish stings 2 people in the middle of the ocean — forcing them to be airlifted to hospital

Tetrodotoxin, which is also found in some newts, frogs and puffer fish, stops nerves from signaling to muscles by blocking sodium ion channels. It rapidly weakens and paralyzes muscles, including those needed to breathe, which can lead to respiratory arrest and death. Tetrodotoxin can start working quickly or take hours to paralyze muscles, so people can die anywhere between 20 minutes and 24 hours after the toxin enters the body, according to the Centers for Disease Control and Prevention (CDC). 

There is no known antidote, so all healthcare practitioners can do is provide supportive care or use a ventilator if patients become unable to breathe, according to the CDC.

Blue-ringed octopuses do not create tetrodotoxin themselves. Instead, the toxin is produced by symbiotic bacteria that live in the creatures' salivary glands, according to the Australian Institute of Marine Science. Tetrodotoxin is found throughout the octopus's tissues, which makes them some of the few animals that are both poisonous and venomous. It also means that a person can receive a lethal dose just by touching the tiny cephalopods.

The octopuses' iridescent blue rings, which are given off by special color-changing organs, flash when they feel threatened to warn predators of their toxicity. 

Despite being so toxic, only three people are known to have been killed by blue-ringed octopuses, according to WebMD. But there have been plenty of close calls.

In March, a woman survived being bitten twice on her abdomen by a blue-ringed octopus hiding in a shell she found while swimming on a beach near Sydney.

In 2006, a 4-year-old boy was almost killed after he was bitten by an octopus he picked up on a beach in Queensland. The boy vomited several times before developing blurred vision and then losing control of most of his muscles, according to a case report published in the journal Clinical Toxicology. After spending 17 hours on a ventilator, he eventually made a full recovery. 

Experts warn that warmer waters during Australia's summer could raise the risk of more people encountering the toxic cephalopods. "They're very good at hiding so we wouldn't normally see them that often but they are there," Jennifer Verduin, an oceanographer at Murdoch University in Perth, told PerthNow.

Two new species of pygmy squid have been found in the subtropical waters of a Japanese island. These cephalopods, which are smaller than paper clips, find refuge in the coral beds and seagrass fields of Okinawa and take their names from- fairies in Japanese folklore and martial arts.

The two newly discovered creatures were described in a study published last month in the journal Marine Biology.

Related: Watch a see-through squid with demon-like eyes swim in Alaska's deep waters

 The Ryukyuan pygmy squid (Idiosepius kijimuna) derives its species name, "kijimuna," from a mythical creature in Okinawan folklore. Kijimuna are said to be red-haired, childlike creatures who live in banyan trees. Similar to kijimuna, I. kijimuna is slightly red and lives in the seagrass forests close to shore, up to 6.6 feet (2 meters) below the surface. Although the species was found back in 2018, researchers had too few specimens to write a formal description at that time, the team wrote in the study. 

The second species, the Hannan's pygmy squid (Kodama jujutsu), takes its name from underwater photographer Brandon Ryan Hannan, who originally found the creature clinging to the underside of a coral reef. This species represents a whole new genus, Kodama, also named after a mythical being. According to the new study, Kodama are ghostly, rounded tree spirits believed to dwell in ancient forests. Their presence is believed to be a sign of a healthy forest.

I. kijimuna swims smoothly, while K. jujutsu bobs along with its arms splayed outward, in order to catch hapless shrimp. These predatory water acrobatics led to the species name "jujutsu" (also spelled "jujitsu" or "jiujitsu"), a martial art. 

"Jiu-jitsu revolves around grappling and using your opponent's strength, and the Kodama jujutsu preys on shrimp larger than itself by grappling with its small arms," co-author Jeffrey Jolly, of the Marine Climate Change Unit at the Okinawa Institute of Science and Technology Graduate University, said in a statement.

Collecting these tiny creatures was tricky;  both species have a maximum length of about half an inch (1.2 centimeters). 

"There are so many other things to look at, that finding a small squid the size of a pinky fingernail is not easy," Jolly said. Not only are both teensy squid nocturnal , but according to the study, the Ryukyuansquid appear only in the winter. Their whereabouts during the summer months is a mystery.

Though these sea-dwelling creatures were discovered recently, land use threatens their habitats. 

Researchers have discovered a new species of bright-yellow "margarita" snail hiding in plain sight on a coral reef in the Florida Keys. The tiny invertebrate, which lacks a traditional snail shell, can shoot out toxic mucus webs.

The newfound species, named Cayo margarita as an homage to the late Jimmy Buffett, was discovered on Florida's Coral Reef, the only barrier reef system in the United States. The vibrant hue of the snail and its close proximity to the Florida coastline inspired researchers to name the snail after "Margaritaville," the song by Buffett, who died on Sept. 1.

The genus, Cayo, translates to "low island" and describes how the snails' circular bodies appear on the reef.  

C. margarita grows to around 0.4 inches (1 centimeter) and uses its toxic mucus webs to catch plankton, algae and detritus. These snails spend their entire lives anchored to the same spot of the reef and rely on ocean currents to waft food past their mucus webs. 

The researchers described the newfound snail species in a study published Oct. 9 in the journal PeerJ, along with a closely related lime-green snail, named Cayo galbinus, that was recently discovered by the same researchers on coral reefs in Belize.

Related: 10 bizarre deep sea creatures found in 2022

The two species belong to the family Vermetidae, also known as the worm snails, because they do not use their shells to protect their soft bodies. Instead, their modified shells act as a tether that holds them to the reef.

"They are related to regular free-living snails, but when the juveniles find a suitable spot to live, they hunker down, cement their shell to the substrate, and never move again," study lead author Rüdiger Bieler, curator of invertebrates at the Field Museum in Chicago, said in a statement. It is interesting to see two related animals use the same body part for something completely different, he added.

The new species are closely related to the Spider-Man snail, Thylacodes vandyensis, which was discovered in the Florida Keys by Bieler and his team in 2017. As its name suggests, T. vandyensis also shoots out chemically enriched mucus webs.

The researchers think the toxic Cayo snails' bright colors are a warning to other animals to "deter the neighbors from getting too close," Bieler said. This would explain how they are able to live out in the open without any protective shell, he added.

Related: 13 of the most venomous sea creatures lurking in the water

Researchers initially thought the two newfound snails could be related sub-species that had altered their colors based on their location. But this turned out not to be the case.

"Initially, when I saw the lime-green one and the lemon-yellow one, I figured they were the same species," Bieler said. "But when we sequenced their DNA, they were very different."

C. margarita and C. galbinus could be some of the few marine creatures that may thrive as a result of climate change. The snails prefer permanently anchoring themselves to dead corals, which will become increasingly common as ocean temperatures rise and corals bleach themselves. However, dead reefs could mean there is less food available to them.

The discovery of C. margarita is a reminder that there are lots of undescribed species hiding in plain sight.

They live in a frequently visited reef, and even then "we had to look very closely" to see them, Bieler said. "It's another indication that right under our noses, we have undescribed species."

Name: Mangrove leaf slug (Elysia bangtawaensis)

Where it lives: Shallow pools of water in the mangrove forests and swamps of southeast Asia and Australia

What it eats: The content of tiny algal cells

Why it's awesome: In addition to looking like a starry night sky, this fabulous slug belongs to the sacoglossans, also known as the "solar-powered sea slugs" — the only known group of animals that can photosynthesize by retaining chloroplasts from algae.

Mangrove leaf slugs have seven to nine sharp teeth, which they use to puncture algal cells to then suck out the good stuff inside. That includes chloroplasts, the cellular structures plants use to transform sunlight into sugars during photosynthesis. Mangrove leaf slugs, which grow up to 2 inches (5 centimeters) long, use the chloroplasts they ingest to power themselves, enabling them to survive without food for two to three months.

Related: This sea slug can chop off its head and grow an entire new body, twice

As well as producing energy, chloroplasts tint these slugs a dark, leafy-green color. This helps mangrove leaf slugs blend into their surroundings and go unnoticed by potential predators, such as crustaceans and birds, as they lounge in shaded pools amid the mangrove trees.  

After a few months, however, the chloroplasts start to shrink and the slugs turn a yellowish color, at which point they have to replenish their photosynthetic machinery with another meal of algae. Once they have fed, the famished slugs regain their leafy-green color.

And if their photosynthetic abilities weren't weird enough, mangrove leaf slugs are simultaneous hermaphrodites, meaning each slug has the sexual organs of both sexes. To reproduce, two slugs hug tight and insert their penises into each other's vaginas at the same time. After sex, the slugs sometimes form a ball as they withdraw their penises. They then lay egg strings up to 28 inches (71 cm) long and coil them around solid features on the swampy substrate. The eggs hatch within a week, releasing a fresh batch of tiny mangrove leaf slug larvae.

 Image courtesy of Nick Volpe Wildlife Photography. 

Name: Green-banded broodsac (Leucochloridium paradoxum)

Where it lives: Europe, North America and Japan

What it eats: Waste in the digestive tracts of birds, before it is excreted

Why it's awesome: This parasitic flatworm is best known for creating disco zombies: It takes over the bodies of amber snails (Succinea) by clambering into their eyestalks and forcing them to dance to attract birds' attention. 

A snail first comes into contact with L. paradoxum via bird droppings, which contain the eggs of the green-banded broodsac. Upon hatching, the larvae move to the tentacles of the snail and create a sac. As this matures, it grows and replaces the eyestalk of the snail, effectively blinding it and preventing it from drawing the tentacle back into its body. 

Related: Horrifying photo captures moment parasitic fungus bursts from huge spider's body

It also becomes colorful and pulsates at a rate of 60 to 80 contractions per minute, creating a disco-like vibe. 

The broodsac also takes over the snail's brain. As a neuroparasite, it infects the nervous system of its mollusk host and controls its behavior. The snail is then forced to go to well-lit and more-exposed areas, such as the surface of a leaf, where it looks tantalizingly like a caterpillar to unsuspecting birds. 

Once ingested, the parasite matures into an adult, mates with other adults and produces eggs that are released into the bird's droppings, kicking off the cycle again. 

If the snail is lucky, only its tentacle is taken by the bird. In that case, the snail remains blind until the tentacle regrows — meaning it can be reinfected and again act as a host for the parasite.

Researchers exploring an underwater mountain in Hawaii's deep sea recently stumbled across a rare, "ghostly" dumbo octopus — one of the deepest dwelling octopuses on Earth — flapping its large ear-like fins as it swam near the seafloor, a new video reveals. 

The unidentified species of dumbo octopus, from the genus Grimpoteuthis, was spotted Sept. 13 by researchers aboard Ocean Exploration Trust's (OET) Exploration Vessel "Nautilus." The team was exploring a seamount in the north of Papahānaumokuākea Marine National Monument (PMNM) — one of the world's largest marine protected areas — using a remotely operated vehicle (ROV) at a depth of around 5,500 feet (1,675 meters) when they came across the pale white cephalopod, researchers wrote in a statement. 

Video footage from the dive, which was live-streamed online, shows the dumbo octopus slowly pushing itself through the water with its ear-like fins just a few feet above the seafloor. This unusual form of locomotion strongly resembles the flying elephant Dumbo, from the classic Disney film, which inspired these octopuses' name. 

"Oh, look at the flappy ears!" one researcher exclaimed during a commentary of the live feed. "I'm so glad we got to see this beautiful creature," another added, "I've never seen one before."

Related: 10 bizarre deep sea creatures that washed ashore in 2022 

There are 15 species of dumbo octopus in the genus Grimpoteuthis, which is the deepest-dwelling known group of octopuses — most of which live deeper than 13,100 feet (4,000 m), according to the ocean conservation nonprofit Oceana. These creatures spend most of their lives hovering around the ocean floor in search of their prey.

The dumbo octopus' style of swimming is quite different to most other cephalopods, which use a funnel-like organ called a siphon to move by shooting out jets of water. This group also differs by having webbed arms and the female's being able to store sperm to fertilize their eggs at a later date, according to Oceana. Because it rarely encounters predators, dumbo octopuses do not have any ink sacs and have a reduced camouflage ability. 

The largest dumbo octopus ever found measured a whopping 5.9 feet (1.8 m) long, according to Oceana. But most individuals are between 8 to 12 inches (20 to 30 centimeters) long. It is unclear how large the octopus in the new video is.

Because of their deep sea habitat, dumbo octopuses are rarely seen in the wild and most of what we know about them comes from ROV sightings and individuals that get dragged up to the surface in fishing nets.

In 2020, scientists spotted a dumbo octopus at a depth of around 22,800 feet (6,950 m) in the Java Trench — the deepest part of the Indian Ocean. Another Nautilus expedition filmed a dumbo near Monterey Canyon, off the California coast in 2018. That same year, a National Oceanic and Atmospheric Administration (NOAA) expedition captured the first video of a dumbo hatchling in the mid-Atlantic. 

In 2021, researchers named a brand new species of dumbo octopus, the emperor dumbo (Grimpteuthis imperator), which was discovered near a seamount in the Pacific Ocean.  

A diver in Washington has captured stunning photos of a massive, alien-looking octopus in shallow water along the state's coastline. The rarely seen cephalopod, which spends most of its life in the deep sea, had injuries that suggest it may have been recently attacked by a cookiecutter shark.       

Underwater photographer Eric Askilsrud, who is based in Washington, snapped the pictures on Sept. 8 while diving at Tongue Point in the Salish Sea, near the Canadian border. Askilsrud encountered the octopus in 10-foot-deep (3 meters) water while exploring a kelp canopy. The unusual-looking cephalopod was around 3 feet (0.9 m) long.

"It was floating motionless with its tentacles down," Askilsrud told Live Science. At first, Askilsrud thought it was a kelp tangle, but he soon realized he was looking at a "very bizarre-looking" octopus.

Askrilsrud had no idea what species the octopus belonged to, so he sent his photos to Gregory Jensen, a marine biologist at the University of Washington, who identified the creature as a seven-arm octopus (Haliphron atlanticus). 

Related: 10 bizarre deep-sea creatures that washed ashore in 2022

Seven-arm octopuses, also known as blob octopuses or septopuses, are one of the largest octopus species on the planet — capable of reaching a maximum length of around 11 feet (3.4 m). Despite the name, these octopuses do actually have eight arms. But the males are known to hide their hectocotylus — a specialized arm used to fertilize eggs — in a sac beneath their right eye, which is how the name originally came about. 

Severn-arm octopuses usually live in deep waters far from shore, according to the Monterey Bay Aquarium Research Institute (MBARI). As a result, most of what we know about the species comes from remotely operated vehicle (ROV) footage, or when specimens wash ashore, like one found in Puget Sound, Washington in 2020.

Related: How do octopuses change color?  

In 2017, an ROV operated by MBARI filmed a seven-arm octopus feeding on an egg-yolk jellyfish (Phacellophora camtschatica), suggesting that the species mainly feeds on slow-moving jellyfish, rather than hunting fish or crustaceans. 

It is unclear which predators may target seven-arm octopuses. But strange round marks on the recently photographed individual may have been inflicted by a cookiecutter shark (Isistius brasiliensis), a small shark that is known to bite eerily circular chunks of flesh from a range of different marine animals.

Another seven-arm octopus was also recently seen in the shallows of the Salish Sea. On Sept. 17, Cam Polglase filmed an individual at Ogden Point near Victoria in British Columbia — just 23 miles (37 kilometers) from Tongue Point. It is currently unclear if this is just a coincidence, or if there is something causing these octopuses to head into shallower water.

A research vessel off the coast of the Galapagos Islands recently spotted a rarely seen, ghostly squid with weak, sucker-less tentacles floating in the deep, marking only the second time this elusive species has ever been filmed alive. 

Researchers from the Schmidt Ocean Institute, in collaboration with the Charles Darwin Foundation and Parque Nacional Galápagos, spotted the ethereal cephalopod, dubbed Grimalditeuthis bonplandi, using a remotely operated vehicle (ROV) during an expedition to hydrothermal vents.  

G. bonplandi can grow up to 10 inches (25 centimeters) in length. These squid have fragile bodies and are slow swimmers. According to the Schmidt Ocean Institute, the species inhabits depths of 660 to 5,000 feet (200 to 1,500 meters). Although believed to exist worldwide, the squid are rarely encountered — until 2005, scientists had only studied dead specimens that came from the stomach contents of sperm whales (Physeter macrocephalus).

Related: What is the largest squid in the world?

Unlike other squid, G. bonplandi has feeding tentacles with no suckers. Other cephalopods whip and thrash, grabbing their prey with their tentacles and trapping them with their suckers, but G. bonplandi is thought to be a graceful feeder that undulates its tentacles to lure small shrimp and other crustaceans. 

Early research collected from dead specimens made it clear that this squid lacked muscle in its tentacles. In 2005, scientists  spotted the creature in the Monterey Canyon off central California and recorded its strange behavior for 22 minutes. At that time, the creature stayed still, as if stunned. Only the ends of its tentacles waved and fluttered. This behavior led scientists to speculate how the animal captures its prey. It could be mimicking the movement of a small fish or worm, luring creatures by resembling their prey — a method called aggressive mimicry, which is common in other cephalopods. However, with the limited video observations and infrequent encounters, this is uncertain.

There is still much to learn about these mysterious creatures, but ROVs have made it possible to capture illuminating footage to inform new theories until the next live sighting.

An alien-looking, see-through squid with demonic red eyes has been filmed in the deep waters off the coast of Alaska.

Researchers from the National Oceanic and Atmospheric Administration (NOAA) Ocean Exploration team spotted the glass squid (Taonius borealis) on July 15 while operating a remote-operated vehicle (ROV) at a depth of around 2,300 feet (700 meters) in the Pacific waters surrounding Alaska's Aleutian Islands. The dive was the first of NOAA's Seascape Alaska 3 expedition onboard the NOAA ship Okeanos Explorer, which aimed to map unexplored areas of the deep sea in the state's exclusive economic zone (EEZ).

Video footage of the encounter shared Aug. 16 on NOAA's Ocean Explorer YouTube channel shows the inverted squid slowly descending through the water, with its mantle — the main part of a squid's body that contains all its vital organs — pointing downward and its small arms appearing to form a single hat-like mass above the eyes at the top of its body. It is unclear how large the squid in the video is, but the species' mantle can grow to a max length of around 26 inches (66 centimeters), according to the International Union for Conservation of Nature (IUCN).

Related: Weird-eyed strawberry squid spotted in 'twilight zone' off California's coast 

"This is a fairly common squid in these waters, but the close-up imagery captured here was anything but [common]," NOAA representatives wrote on YouTube.

One of the most striking parts of the new video is the see-through squid's visible internal organs. The largest red-colored organ is the digestive gland. It is flanked on either side by two white sacs, which are the gills. 

During the video, there is a brief moment in which one of the squid's eyeballs appears to briefly retract within the surrounding purple discs. This behavior is the equivalent to humans and other animals blinking, NOAA representatives wrote.

The squid also has white crescent-shaped structures beneath each eye. These are photophores, or light-producing organs used to attract prey, including shrimp, small fish and other squid, NOAA representatives wrote.

There are more than 60 known species of glass squid within the family Cranchiidae, and each have at least partially translucent skin. The largest glass squid is the colossal squid (Mesonychoteuthis hamiltoni), which reaches 33 feet (10 m) long and is the heaviest squid in the world. 

On March 4, María Branyas Morera turned 116. In January, the great-grandmother, who was born in San Francisco in 1907 and now lives in a nursing home in Catalonia, Spain, became the world's oldest person following the death of Sister André (née Lucile Randon), a French nun who lived to be 118.

Branyas Morera, who goes by the nickname "super grandmother," has lived through the 1918 Spanish flu pandemic, both World Wars and the Spanish Civil War. She also survived a bout of COVID-19 just weeks after turning 113, according to Guinness World Records.

Branyas Morera attributes her long life to a number of things, from enjoying nature and good company to "staying away from toxic people," but she ultimately credits her extreme longevity to "luck and good genetics," she told Guinness World Records.

Branyas Morera is part of a super-exclusive club: She is a supercentenarian, meaning a person who is 110 years or older. For instance, in Japan only about 30 people can claim this title, meaning only 1 in 871,600 people reaches this milestone, according to the New England Centenarian Study. In comparison, approximately 573,400 centenarians (people who are at least 100 years old) were alive worldwide in 2021, according to the United Nations.

Related: We're nowhere near reaching the maximum human life span, controversial study suggests

People like Branyas Morera could help scientists better understand what allows some people to live so long. Is their longevity just luck, or is it due to good genes and other factors? And which genes are the most critical to defying the aging process? 

Studying centenarians and supercentenarians also could reveal insight into the maximum life span for humans — and potentially ways to extend it. Supercentenarians tend to have certain lifestyle factors in common, which may help people overall lead longer, healthier lives. But to dramatically extend the human life span, scientists may have to venture beyond Homo sapiens and look to our long-lived animal counterparts.  

Are good genes the key to extreme longevity?

Genes clearly play a role in longevity. Children and siblings of centenarians tend to live longer than average, according to Medline, a service of the National Library of Medicine. And a 2016 study in the journal Aging found that genes tied to immune function and cell repair were more active in these extremely old people. 

In general, scientists estimate that about 25% of life span is determined by genetics. But which specific genes, if any, play the largest roles in aging? 

For decades, Dr. Annibale Puca, a professor of genetics at the University of Salerno in Italy, has been trying to answer that question. 

In 2011, Puca discovered a human gene called BPIFB4 that halts cardiovascular aging and even reverses some aspects of aging when inserted into mice. In a 2015 paper in the journal Circulation Research, Puca and his colleagues showed that a certain version of BPIFB4 was associated with exceptional longevity and was overrepresented in centenarians. Those with two copies of the gene variant had less cardiovascular illness, lower blood pressure and less arteriosclerosis, compared with people without two copies of the gene variant. Puca estimates that about 10% of humans have this gene variant. 

Could BPIFB4 partly explain why certain people are predisposed to living longer than others? Puca thinks so. "You don't live to 110 unless you have good genes," he told Live Science. 

In follow-up research, Puca's team not only halted heart damage in middle-age and elderly mice but also reversed the biological age of the mice's hearts by the human equivalent of 10 years, according to the study.

"In the lab, we were able to regenerate their blood vessels and vascular (circulatory) systems, which converted inflammatory cells into anti-inflammatory cells," Puca said. "We found that cardiovascular function was corrected in the mice."

In a paper published Jan. 13 in the journal Cardiovascular Research, Puca and his team introduced the gene into heart cells collected from organ donors who had died of heart failure. As with the lab mice, the mutated gene rewound the clock and reversed cardiac aging by increasing cardiovascular function by 20% to 60%. Inflammatory cells also morphed into healthy cells. 

"We now know that it works in human tissue," Puca said. 

Related: Human life span may have an 'absolute limit' of 150 years

Puca's colleague Paolo Madeddu, a professor of experimental cardiovascular medicine at the University of Bristol in England, said that if more research backs up the effect, BPIFB4 could be inserted via gene therapy into the cells of people who don't carry the gene. However, the application of this treatment is still many years away.

"You would need to repeat the therapy over and over again," Madeddu told Live Science. "It doesn't last forever." 

The researchers are currently testing whether the protein the gene codes for, rather than the anti-aging gene itself, can have similar effects in cardiac cells.

BPIFB4 isn't the only gene tied to a longer life span. In 2019, researchers described a so-called "longevity gene," Sirtuin 6 (SIRT6), in the journal Cell. SIRT6 helps repair DNA, which aging cells can't repair efficiently, leading to gene mutations that can drive cancer and other illnesses. 

The researchers analyzed the activity of SIRT6 in a range of rodent species, from mice to beavers, and found that the animals with the longest life spans also had the most efficient DNA repair capabilities due to their SIRT6 proteins being "more potent," according to the study.

Last year, a follow-up study in The Embo Journal looked at a cohort of 450 Ashkenazi Jewish centenarians and 550 Ashkenazi Jewish individuals who didn't have a family history of extreme longevity. The researchers discovered that a "novel rare variant," which they dubbed "centSIRT6," was twice as prevalent in the centenarians than in the latter group. 

In lab dishes, they also found that centSIRT6 not only helped repair broken DNA but also "more robustly kill[ed] cancer cells" when compared with the more common version of SIRT6, according to the study.

Environmental factors tied to extreme longevity

While variations in human genes affect longevity, environmental factors also play a role. Numerous studies have shown that things like being optimistic, having a healthy diet and not smoking are tied to living a longer life. 

But can supercentenarians tell us about other factors that may extend life span? Some researchers say they've uncovered hints in a surprising place: convents.

Before Branyas Morera held the title of the world's oldest person, a French nun, Sister André, was the oldest living person. That may not be a coincidence. Many Catholic nuns live to become centenarians — and even supercentenarians. But why is this? 

Several years ago, anthropologist Anna Corwin, author of "Embracing Age: How Catholic Nuns Became Models of Living Well" (Rutgers University Press, 2021), spent time at a convent in the Midwest, interviewing the nuns who lived there. Corwin noticed similar patterns in the women's lives that may be tied to longevity.

"It's not specifically because they're nuns that they're able to live for so long, but rather the types of cultural practices they engaged in," Corwin, an associate professor of women's spirituality and anthropology at the California Institute of Integral Studies in San Francisco, told Live Science. 

In general, nuns were living lives full of meaning. It also helped that they were part of a tight-knit, supportive community.

Related: People who live to be 100 have unique gut bacteria signatures

The nuns also tended to reject the stigma around aging. Corwin said they participated in day-to-day activities, such as prayer and socializing, well into old age. And they didn't necessarily view themselves as elderly.

"One of my first months at the convent, I met this 95-year-old woman who was in a wheelchair totally hunched over, who you would imagine couldn't participate in anything," Corwin said. "I asked her what she does with her days, and she said, 'I serve the infirm and visit the elderly.' Sure enough, as I watched her, she would wheel slowly down the hallway and check in on her neighbors in the infirmary to make sure they were doing well."

Corwin concluded that the nun found fulfillment and meaning in life by helping others. She also viewed herself as having autonomy and agency, Corwin said.   

While this evidence may be anecdotal, a study conducted by epidemiologist and leading Alzheimer's expert David Snowdon backed up these observations. In 2003, Snowdon conducted a longitudinal study of 678 nuns from the School Sisters of Notre Dame, an international organization recognized by the Catholic Church. 

Snowdon found that nuns had "lower all-cause mortality rates than did the general population and this mortality advantage increased over time." In fact, these nuns were "27% more likely to live into their 70s than their lay peers, and their likelihood of living longer increased with time," Corwin wrote in her book. In addition, the nuns were less likely to smoke, and they ate healthily and lived peaceful and communal lives. 

It's not clear how some of the most obvious differences between nuns and the general population — namely, that they make vows of celibacy and don't have children — affect longevity. Some research has found that each child a woman gives birth to shaved off years of a woman's life, while other studies have shown that people with children live longer than the child-free.

What animals reveal about extreme longevity

While human genes and environmental influences may lead to incremental improvements in longevity, to make leaps and bounds, it may help to look to the animal kingdom.

That's what Steven Austad, a distinguished professor in the department of biology at The University of Alabama at Birmingham, is doing.

Last year, Austad, who is also senior scientific director interim chair with the American Federation for Aging Research, wrote a book titled "Methuselah's Zoo: What Nature Can Teach Us about Living Longer, Healthier Lives" (MIT Press, 2022). (The title is a nod to Methuselah, a biblical patriarch who supposedly lived to be 969 years old.) Austad's book focuses on the longest-living animals on Earth, from bowhead whales (Balaena mysticetus), which can live 200-plus years, to Escarpia laminata, a species of tube worm found in the Gulf of Mexico that has an average life span of about 300 years.

However, the creature that captured Austad's attention was the world's oldest animal, a 507-year-old ocean quahog (Arctica islandica) dubbed "Ming the Mollusk." 

One factor in Ming's longevity is clearly its underwater environment: It's "cold, safe and deficient of any real predators," Austad wrote in 2022 in an article for The Atlantic.

"Mollusks like Ming spend most of their lives living in really cold water burrowed in the mud and covered by a thick shell," Austad told Live Science. "Living at the bottom of the ocean is very stable, and being in the mud probably adds a layer of safety as well as having a shell."

Austad suspects that when animals aren't prone to predation or to the vagaries of a harsh or chaotic environment, evolution favors physiology that lasts a long time.

Bivalves also draw heat from their surroundings rather than generating it themselves the way humans and other mammals do. This may lead to creatures like Ming that are better protected from oxidative stress, Austad hypothesized. (Oxidative stress, or damage to tissue by chemically reactive oxygen compounds, has long been linked to aging.) 

To test his theory, Austad and his students brought a variety of mollusk species into their lab, including bay scallops (Argopecten irradians), which live an average of two years; table clams, which can live up to a century; and a handful of super-aging ocean quahogs like Ming, and introduced oxygen-radical generating chemicals to their tanks. The scallops succumbed within two days, while the table clams held on for 11. 

Two weeks into the experiment, the quahogs remained "happy as a clam" despite living in tainted water, Austad said. This suggested that the quahogs were recovering from or preventing oxidative stress.

"As humans, we can't replicate their living conditions, but we can figure out how they do it," Austad said. "[There are] no doubt some genetic tricks, but it could also be something that we could replicate pharmacologically if we understood it well enough." 

Currently, there's only one animal species that could theoretically live forever: the immortal jellyfish (Turritopsis dohrnii). No bigger than a pinky nail, these translucent blobs can turn back their biological clocks when injured and revert into plant-like polyps sprouting from the ocean floor. If enough of these polyps colonize, they can eventually begin to bud and "release medusae that are genetically identical to the injured adult," according to the American Museum of Natural History.  

This shape-shifting is possible thanks to a process known as transdifferentiation, which restarts cell generation and essentially gives these amorphous blobs a second lease on life. For the past three decades, scientists have been studying this mechanism and different ways to apply it to humans. 

So far, no one has pinpointed the reason cells can transdifferentiate. But a 2022 paper published in the journal Proceedings of the National Academy of Sciences found that T. dohrnii had double the DNA repair genes of other jellyfish species. They also had gene mutations that protect telomeres, the caps on the ends of chromosomes, which typically shorten with age, according to the study.

However, that doesn't mean humankind could borrow these genes and seemingly live forever — or become supercentenarians like Branyas Morera, for that matter. Only time will tell.

Editor's Note: This story was corrected on Friday, March 31 at 9:45 a.m. EDT to note that there are only 30 supercententarians alive today in Japan, not worldwide. It was also corrected to note that the U.N. data on the the total number of centenarians alive worldwide was from 2021. 

Due to an editing error, the article also mistakenly said that Snowdon's research compared the health outcomes of nuns with different lifestyles; his research only compared the health outcomes of nuns with the general population, not with each other. That reference was removed on April 4. 

A woman in Australia was recently bitten multiple times by a blue-ringed octopus — one of the world's most toxic animals — and lived to tell the tale.

Blue-ringed octopuses are a group comprising four species: the greater blue-ringed octopus (Hapalochlaena lunulata), the southern blue-ringed octopus (Hapalochlaena maculosa), the blue-lined octopus (Hapalochlaena fasciata) and the common blue-ringed octopus (Hapalochlaena nierstraszi). These octopuses are small enough to fit in the palm of your hand and are covered in tiny rings that flash with an iridescent blue when the animals are threatened. Blue-ringed octopuses also contain tetrodotoxin, a powerful neurotoxin that can paralyze and kill humans even in small doses.

On March 16, the woman was bitten twice on her abdomen by an unknown species of blue-ringed octopus at a beach near Sydney in New South Wales (NSW), Australia. She had collected a small shell while swimming, and when she picked it up to look at it, the tiny cephalopod fell out and landed on her stomach, the NSW Ambulance service wrote on Facebook.

The woman experienced some abdominal pain and was treated with cold compresses before being taken to the hospital to be monitored for more symptoms, according to NSW Ambulance. It is unclear why the woman escaped relatively unharmed.

Related: 30 unusual poisonous animals

Tetrodotoxin stops nerves from signaling to muscles by blocking sodium ion channels. This causes rapid weakening and paralysis of muscles, including those of the respiratory tract, which can lead to respiratory arrest and death. The effects of tetrodotoxin can occur rapidly or have a delayed onset, so death can occur anywhere between 20 minutes and 24 hours after the toxin enters the body, according to the Centers for Disease Control and Prevention (CDC). 

There is no known antidote for tetrodotoxin. All health care practitioners can do is provide supportive care or use a ventilator if patients are unable to breathe, according to the CDC.

Blue-ringed octopuses do not create tetrodotoxin themselves. Instead, the toxin is produced by symbiotic bacteria that live in their salivary glands, according to the Australian Institute of Marine Science. Tetrodotoxin is found throughout the octopus's tissues, not just in specific venom glands, which makes them some of the few animals that are both poisonous and venomous. It also means that a person can receive a lethal dose if one of these octopuses touches their skin.

Despite being so toxic, blue-ringed octopuses have caused only three confirmed deaths, according to WebMD.

The iridescent blue rings that flash on the octopuses' bodies warn predators of their toxicity. They can flash their rings in less than 0.4 seconds, thanks to tiny color-changing organs called chromatophores, which are dotted across the animals' skin.

While blue-ringed octopuses rarely kill people, there have been plenty of close calls.

In 2006, a 4-year-old boy was almost killed after being bitten by an octopus he picked up in a rock pool on a beach in Queensland. The boy vomited several times before developing blurred vision and then losing control of most of his muscles, according to a case report published in the journal Clinical Toxicology. After spending 17 hours on a ventilator, he eventually made a full recovery. 

And in March 2021, a woman was heavily criticized online after sharing a video of herself holding a blue-ringed octopus in Bali, although she did not know it was highly toxic at the time and escaped unscathed, according to Insider.

Blue-ringed octopuses aren't the only animals that contain tetrodotoxin; it can be found in some newts, frogs and puffer fish. 

A diver in Japan swam alongside an unusual companion earlier this month: An 8.2-foot-long (2.5 meter) giant squid. 

Yosuke Tanaka, who co-runs Dive Resort T-Style with his wife in Toyooka City, Japan, got the opportunity on Jan. 6 when a local ferryman called him to say that there was a large squid swimming near the surface off the coast in the Sea of Japan. Tanaka hurried over, he wrote on his blog, and was rewarded with a close-up encounter with one of the ocean's most mysterious creatures.

It was the first time he'd ever swum with a giant squid (Architeuthis dux), Tanaka told Live Science in an email. 

"I felt a little scared because it was so big," he said. 

Related: Giant squid filmed alive for second time in history. Here's the video.

Giant squid typically live in the deep ocean, so they're often only seen as corpses washed ashore or as accidental bycatch in fishing nets. They can grow to 40 to 45 feet (12 to 14 meters) long, a size even more incredible considering that the animals likely only live about five years in the wild, according to the Smithsonian Institution. Their elusive nature means little is known about their daily lives or mating habits, though investigations of their guts reveal that they eat fish and other squid. They're also often found in the stomachs of sperm whales, indicating that they aren't just hunters, but are also hunted.

Though most people won't get a chance to swim alongside a giant squid, Tanaka's encounter was not so surprising to squid scientists. 

"It's unusual any place other than where they saw it," said Michael Vecchione, a zoologist and cephalopod expert at the Smithsonian National Museum of Natural History in Washington, D.C. "Actually, in the Sea of Japan it turns out that it's fairly common to see giant squids at this time of year." 

Japanese zoologist Tsunemi Kubodera, who captured the first photographs and video of living giant squid in their native habitats, has documented large numbers of giant squid between January and March in the coastal waters of the Sea of Japan. In a 2016 paper, Kubodera and his colleagues reported finding 57 giant squid in just those three months, 28 of which were alive. 

The squid, unfortunately, do not fare well in this region at this time of year. According to Kubodera's research, the squid travel through the Tsushima Strait between South Korea and Japan as part of their typical north-south migration. Those that time the migration wrong, however, get trapped by cold water at the depths where they usually swim. 

"When that happens, they can't stay in the really deep water that they usually stay in," Vecchione told Live Science. "They come up close to the surface, and then the surface water gets cold. When you see them up close to the surface, they're not healthy." 

Tanaka's video shows a squid in rough shape, said Sarah McAnulty, a squid biologist who runs a Squid Facts hotline ( Text "SQUID!" to 1-833-724-8398) and the executive director of Skype a Scientist, a science outreach program. 

"You can tell this squid is approaching the end of its life by looking at its skin," McAnulty told Live Science in an email. "A healthy giant squid should have smooth shiny skin and be kinda red. This poor thing has been through it!"

Tanaka said he swam near the squid for about a half-hour. The squid was swimming slowly, he said, but was trying to move away from him. 

Though giant squid have a fearsome reputation in literature — think "20,000 Leagues Under the Sea" by French writer Jules Verne — the chance of anyone being attacked by a giant squid is extremely small, Vecchione said. The only encounters with humans tend to be when people poke or prod at the squid, as in a 2017 incident caught on video when a surfer lassoed an injured juvenile squid, which then wrapped its tentacles around the surfboard. No humans were injured.  

Legends about gargantuan squid have existed for millennia, with photos confirming their existence nearly 150 years ago. But what is the largest squid in the world?

Depending on how you measure, there are two contenders. The giant squid (Architeuthis dux) is the longest squid, and the colossal squid (Mesonychoteuthis hamiltoni) is the heaviest.

The giant squid, found in every ocean, is estimated to reach up to about 40 to 45 feet (12 to 14 meters) long from the tip of its body to the tip of its tentacles and weigh about 600 pounds (270 kilograms), Heather Judkins, a cephalopod expert at the University of South Florida at St. Petersburg, told Live Science. There have been claimed sightings of giant squids up to about 66 feet long (20 m), but they have not been verified, according to Two Oceans Aquarium in Cape Town, South Africa. 

The colossal squid, which lives in Antarctic waters but may venture as far north as New Zealand, is estimated to reach about 30 to 33 feet (9 to 10 m) long. However, what it lacks in total length compared with the giant squid, it makes up for in weight — it can reach about 1,000 pounds (450 kg), Judkins said. This likely makes the colossal squid the most massive invertebrate on Earth, according to ocean nonprofit Oceana.

Giant squid and colossal squid have the largest eyes of any living animal, and possibly the largest eyes that have ever existed in the animal kingdom, according to the Museum of New Zealand. They measure about 11 inches (27 centimeters) wide, about the size of a soccer ball, a 2012 study in the journal Current Biology noted.

Each colossal squid eye is also equipped with a light-emitting organ known as a photophore, the Museum of New Zealand said. Colossal squid use these photophores like headlights to see in the dark. (Giant squid eyes lack photophores, Judkins said.)

The colossal squid also has the largest beak of any squid, made of a material similar to what human fingernails are made of. The squid uses its beak to slice a meal into bite-size pieces before it enters the mouth, and a tooth-covered, tongue-like organ called the radula shreds food further once it's inside the beak.

Related: See 15 crazy animal eyes

Both huge squid species eat fish and other squid. After they reach adulthood, the only regular predator they face is likely the sperm whale, according to Two Oceans Aquarium. Colossal squid might form as much as 77% of a sperm whale's diet, according to the Museum of New Zealand.

Because the ocean is so vast and the squid live so deep, these sea monsters are rarely seen, the Smithsonian noted. Although both the ancient Greek philosopher Aristotle and the ancient Roman scholar Pliny the Elder recounted details about huge squid, according to Two Oceans Aquarium, the first photo of such an enormous squid wasn't taken until 1874, when Rev. Moses Harvey of Newfoundland captured a picture of a dead giant squid from a fisherman who caught it by accident, the Smithsonian said.

Most of what scientists know about giant squid comes from remains discovered floating on the ocean surface, washed up on beaches or within sperm whale stomachs, a 2013 study in the journal Proceedings of the Royal Society B noted. The same holds true for colossal squid, according to the Museum of New Zealand.

Scientists did not manage to capture a photo of the adult giant squid in its natural habitat till 2004, and the first video footage of an adult giant squid in the wild was not taken until 2012, Britannica explained. Similarly, no one had ever seen an intact colossal squid until 2003, according to the Museum of New Zealand. An international expedition to Antarctica this December will attempt to find and film the colossal squid in the deep sea for the first time.

"The ability to see these animals in their natural habitat is amazing," Judkins said. "To get the opportunity to capture them with remotely operated floating camera systems is great. It's an excellent way to observe behaviors."

One of the deep sea's most elusive and spectacular creatures, the giant squid (Architeuthis dux), recently astonished a group of tourists after it washed up as a half-eaten corpse on a New Zealand beach. A tour guide who was leading the group at the time described the chance finding as a "once-in-a-lifetime" experience. 

The colossal cephalopod, with a mantle measuring around 13 feet (4 meters) long, was discovered Sept. 9 on the beach at Farewell Spit, a nature reserve in the north of South Island. A lone guide from the nature tour agency Farewell Spit Tours found the remains, which were half buried in sand, and quickly alerted a nearby tour group to come and take a look. After diverting to examine the squid's corpse, the group spent time marveling at the amazing animal and snapping photos next to the rare remains.

"It's not a common find on any beach, so if you're able to be there at the right time, it's a once-in-a-lifetime opportunity," Anton Donaldson, the Farewell Spit Tours guide who was leading the group, told The New Zealand Herald. But it was also sobering to see such a "magnificent example of a large sea creature" dead on the land, he added.

Giant squids are the second-largest squids in Earth's oceans — dwarfed only by the colossal squid (Mesonychoteuthis hamiltoni) — and can measure up to 43 feet (13 m) long. The hefty cephalopods, which are thought to be the real-life inspiration for the massive mythological sea creature known as the "kraken," live in deep water more than 2,950 feet (900 m) below the surface and are rarely seen in the wild.

Related: Beached sperm whale in Australia shows scars from tussle with a giant squid 

It is unclear exactly how long the dead squid's entire body measured, because most of its tentacles were incomplete or buried beneath the sand.

"It looked like [the tentacles] had been chewed back by some other sea creatures, such as small sharks or fish," Donaldson said. "While I don't know for sure, I imagine it had been floating out there for a period of time and had washed up."

The tour company informed New Zealand's Department of Conservation about the beached squid, and the agency will likely attempt to retrieve the remains so they can be studied, according to The New Zealand Herald.

Seeing a giant squid up close may be a "once-in-a-lifetime" experience for most people, but this isn't the first time that remains of the deep-sea giants have beached on Farewell Spit's shores. In total, at least six dead giant squids have washed up on the beaches of the nature reserve in the last 30 years, a Farewell Spit Tours representative told Live Science in an email. 

In 2019, on the same part of the beach, another tour group came across a fully intact giant squid measuring 18 feet (5.5 m) long, Farewell Spit Tours representatives said in a statement at the time of the incident.

South Africa is another location where dead giant squids are known to wash ashore. In April, an 11.5-foot-long (3.5 m) specimen washed up near Kommetjie, and in August, a 14-foot-long (4.3 m) squid was found on a beach near Cape Town.

Originally published on Live Science.

The massive, sucker-covered carcass of a giant squid washed onto the rocky shore of Scarborough Beach in Cape Town, South Africa, Tuesday (Aug. 16). The beast, which measured nearly 14 feet (4.3 meters) long, was the second giant squid to crop up on a beach in the region this year, according to the South African news site news24.

The last known giant squid (Architeuthis dux) to wash ashore near Cape Town showed up about 6 miles (10 kilometers) northwest of Scarborough Beach, on Long Beach in Kommetjie, on April 30, Live Science previously reported. That cephalopod measured roughly 11.5 feet (3.5 m) long. For comparison, the largest giant squid ever seen measured a whopping 43 feet (13 m) long, and some studies suggest that the creatures could potentially reach 66 feet (20 m) long, although no squid of such size has ever been spotted. 

The squid that washed onto Scarborough Beach this week seemed to be another A. dux specimen, said Mike Vecchione, a National Oceanic and Atmospheric Administration invertebrate zoologist stationed at the Smithsonian's National Museum of Natural History in Washington, D.C. "Although other large squids exist, I am fairly certain this is a true giant squid," he told Live Science in an email. 

Other squid species, including the colossal squid (Mesonychoteuthis hamiltoni), rival A. dux in terms of sheer size, and some scientists argue that the Architeuthis genus actually includes a variety of giant squid species, rather than A. dux alone, according to the Smithsonian. 

Related: Why are there so many giants in the deep sea? 

Without an examination of its internal organs, it's difficult to guess how the Scarborough Beach squid perished, Vecchione said. "Note that most of the skin has abraded and some of the arms are broken off, but this (especially the skin abrasion) can result from washing up on the rocky shore." The remaining skin on the squid's mantle — the muscular sheath that houses its organs — gleamed ghostly white in the sun. 

It may be that the squid ventured into shallow, near-shore waters to feed and got struck by a ship propeller, "but this is difficult to prove without witnesses," Dylan Clarke, a marine scientist and curator at Iziko South African Museum, told news24. "The literature … suggests that they come up into shallower waters because they display a behaviour called diel vertical migration. In other words, they venture into shallower waters during the evening to feed and migrate back to deeper waters during the day."

Giant squid generally live in frigid waters some 1,640 to 3,280 feet (500 to 1,000 m) beneath the ocean surface, and they use their dinner plate-size eyes to peer through the inky darkness, according to the Smithsonian. Based on where the animals have washed ashore, scientists think the squids may inhabitat all the world's oceans, but they're most frequently seen on the shores of New Zealand and Pacific islands, on the east and west sides of the North Atlantic, and in the South Atlantic along the African coast.

"Strandings of Architeuthis on South African shores are not unusual at all," Vecchione told Live Science. "It is one of several places around the world where they show up regularly." 

Officials gathered tissue samples from the squid carcass on Scarborough Beach, and these will soon be examined by researchers at the Iziko South African Museum, Gregg Oelofse, the City of Cape Town coastal manager, told news24. Scientists could use such samples to sequence the animal's DNA and run chemical analyses to detect pollutants and stable isotopes — nonradioactive chemical elements with varying numbers of neutrons in their nuclei — in its flesh, Vecchione said. The isotope analysis would provide hints about the squid's feeding history, as would an examination of the animal's digestive system. 

In addition, scientists could determine how old the squid was based on its reproductive organs and statoliths, small mineralized masses that sit inside sensory organs in the squid's head and accumulate "growth rings" over time, Vecchione said. Past studies of these statoliths suggest that giant squid can live to be about 5 years old, according to the Smithsonian.

"The availability of information on giant squids is relatively poor and is either based on dead or dying animals that have been washed ashore or captured in commercial trawl nets," Clarke told news24. The newfound Scarborough Beach squid will join a collection of giant squid specimens at the Iziko South African Museum that were largely acquired through such strandings or incidental catches during bottom trawls, he said.

Originally published on Live Science. 

While nearly all of the world's most treasured gemstones can be found buried underground, pearls hide in a far more unexpected setting: inside a shell.

So how exactly did these iridescent jewels wind up in such an unlikely place?

Despite what many people may think, pearls aren't the result of an errant speck of sand weaseling its way inside the shell of an unsuspecting mollusk. In fact, sand (which is common in the aquatic environments where mollusks live) isn't involved at all. Instead, pearls are formed when an irritant, such as a food particle or a parasite, slips between the shells of an oyster or other mollusk and lodges into its mantle, the muscular wall where its internal organs are located. In an act of self-defense, the invertebrate oozes a liquid containing aragonite (a carbonate mineral) and conchiolin (a protein), and as the secretion intermingles with the intruder, it creates a material called nacre, or mother-of-pearl, according to the American Museum of Natural History in New York City. Over time, these layers of nacre turn into what eventually becomes a pearl.

Related: Which is rarer: Gold or diamonds?

Pearls come in a variety of colors, shapes and sizes, and much like snowflakes, no two are the same — even in the case of cultured freshwater pearls. These commercially farmed gemstones are the result of human intervention, in which a farmer implants a small bead made of shell into the interior of a mussel to kickstart the nacre-secreting process. The vast majority of pearls sold on the market today are cultured, according to the Gemological Institute of America.

The lustrous nature of pearls has made them a coveted item for thousands of years and across many cultures. In Hindu folklore, it was believed that the moon would drip dewdrops into the sea that turned into pearls, while Greek mythology professed that pearls were tears of joy shed by the goddess Aphrodite, according to the American Gem Society.

Regardless of where pearls came from, throughout history, they were often just as valuable — if not more so — as gold and diamonds, often being strung into jewelry or offered as a form of trade. Not surprisingly, pearls became associated with nobility, with Julius Caesar passing a law that only aristocrats could don pearls while in Rome, and Cleopatra dissolving a pearl earring in vinegar and drinking the brew to win a bet against her lover Marc Anthony, according to the Metropolitan Museum of Art.

Today, pearls continue to captivate, thanks to their beauty and the curious nature in which they're formed.

Originally published on Live Science on Nov. 20, 2012 and rewritten on July 22, 2022.

Extremely rare footage of a squid mom carrying a gelatinous string of glimmering pearl-like eggs in her arms has been captured in the dark ocean depths off the coast of California. 

Researchers from Monterey Bay Aquarium Research Institute (MBARI) recently spotted the deep-sea squid (an unknown species in the genus Bathyteuthis.) around 56 miles (90 kilometers) off the coast at a depth of 4,560 feet (1,390 meters), a depth roughly three times the height of the Empire State Building. The team used a remotely operated vehicle (ROV) to capture high-definition footage of the squid and her still-developing offspring, allowing researchers to "examine the pelagic [open-water] parent in astounding detail," MBARI representatives wrote in a description of the video, which they shared July 6 on the MBARI YouTube channel.

It is extremely unusual for female squids to be seen carrying their eggs along with them; such behavior is known as brooding. "Most squids reproduce by depositing egg cases on the seafloor or releasing eggs in a gelatinous mass that drifts in open water," and then abandon their unhatched larva to fend for themselves, researchers wrote in a statement. 

Sometimes "these nurturing mothers will carry the eggs until they hatch to improve their babies' chances for survival," the researchers wrote. But carrying eggs is also likely to be energetically expensive for the mom and increases her risk of being predated, which is why it is uncommon to see this behavior in action. 

Related: Weird-eyed strawberry squid spotted in 'twilight zone' off California's coast 

This is only the second time MBARI researchers have observed this brooding behavior in Bathyteuthis squid, after first glimpsing it in 2005. Only two other species of brooding squid, both from the deep sea, have ever been spotted carrying their eggs in this way. However, the researchers suspect that "other deep-dwelling squids may also turn out to be brooders," according to the statement. 

The overprotective mom in the video appears deceptively large alongside her tiny eggs, but in reality, her mantle — the main part of a squid's body containing all the major organs — can only grow to a maximum length of 3 inches (7.5 centimeters), according to MBARI.

Researchers say that videos like this one show the importance of continuing to explore deeper waters. "The deep ocean is challenging to study and we only get brief glimpses into the behaviors of deep-sea animals," the researchers wrote. "Each observation logged by our ROVs provides another piece of the puzzle and helps improve our understanding of life in the deep."

Originally published on Live Science.

Octopuses might be nature's ultimate weirdos: They have squishy bodies that can squeeze through tiny cracks; eight sucker-covered arms that can be regrown; three hearts that pump blue blood (rich in copper) through their veins; and massive, donut-shaped brains that give them superior intelligence compared with other invertebrates. But octopuses' most awe-inspiring trait is arguably their ability to rapidly change color and blend into their surroundings, camouflaging themselves at will. 

Camouflage is an important skill shared by almost all cephalopods — a group of marine invertebrates that also includes squid and cuttlefish — but octopuses have taken it to a whole other level. These animals have the highest resolution patterns of any cephalopod and display some of the quickest color transitions in the entire animal kingdom. (There are around 300 species of octopus in the order Octopoda. In this article, the term 'octopuses' is used to describe general trends throughout the group, but not every species is capable of changing color, and the camouflaging mechanics they use can vary.)

Octopuses' mastery of camouflage has mystified researchers since the beginning of science itself. Around 2,400 years ago, Aristotle, the ancient Greek philosopher who is often considered one of the founding fathers of modern science, jotted down detailed observations of octopus camouflage — the first known person to do so, Leila Deravi, a biochemist at Northeastern University in Massachusetts who studies octopus camouflage mechanics, told Live Science. But even though octopus camouflage "has been studied and observed for centuries, not a lot of developments have been made" until very recently, she said.

Related: What's the difference between arms and tentacles? 

Here's why: Color changing in cephalopods is a complex process that involves many different microscopic components. This makes it "almost impossible" to answer exactly how it works, Deravi said. However, in the last few decades, cutting-edge technology has enabled researchers to "tease apart" the individual components of cephalopod camouflage and are now beginning to understand how they work, she said. 

What makes an octopus change color?

Octopuses can shift hues because they have chromatophores — tiny, color-changing organs that are dotted throughout an octopus's skin.

At the heart of each chromatophore are tiny sacs filled with nanoparticles of a pigment called xanthommatin, Deravi said. The pigment sacs are surrounded by an elastic matrix that is, in turn, connected to muscle cells that surround the sac in a pointed star shape, she added. As these muscle cells contract, the pigment sac stretches, which enables more light to enter the cell and reflect off the xanthommatin particles. Because xanthommatin absorbs certain wavelengths, or colors, of visible light, the light it reflects back out of the chromatophore is a different color compared with the light that first entered the cell.

There are three layers of chromatophores in an octopus's skin, and each layer has xanthommatin particles that reflect back a different color. The top layer produces a yellow color, the middle layer reflects back a red color and the bottom layer produces a brown color, Deravi said. Octopuses can combine these colors by changing the shape of the chromatophores in each layer, which enables the cephalopods to create a wide array of hues.

Each individual chromatophore, of which there can be tens of thousands or even millions depending on the size of the species, is controlled with direct neural signals from the octopus's brain that causes the muscles surrounding the sac to contract or relax, changing its shape. "It's just like how you would flex your biceps, your brain signals to flex and it flexes," Deravi said. "With the chromatophores, the [octopus's] brain is signaling to pull these muscles to open up these sacs," which then changes the color of the skin.

The Instagram post below shows squid chromatophores contracting and relaxing to the beat of the song "Insane in the Brain," by the band Cypress Hill. In this scenario, the vibrations from the music are misinterpreted as neural signals by the chromatophore muscles.

Chromatophores aren't the only structures involved in the color-changing party. Additional organs, known as iridophores and leucophores, in the skin of certain octopus species can help enhance or alter the colors they produce. 

Iridophores are slightly larger than chromatophores and help create octopuses' more luminescent and metallic colors. Iridophores contain a protein called reflectin, which stacks up inside the iridophores to create a mirror-like effect, according to a 2018 study published in the journal IOP Science. Leucophores are similar in size to chromatophores but have specialized white pigments instead of xanthommatin, which scatter or refract light and help control the contrast and brightness of colors, Deravi said. Both iridophores and leucophores are expanded and contracted by neural signals from the brain, just like chromatophores are. 

Related: What color were the dinosaurs?

Octopuses also possess machinery in their skin that helps them to change their texture, which adds another layer to their camouflage. They have tiny bumps called papillae that can be relaxed, making the skin smooth like seaweed, or contracted, making the skin lumpy and rough like a rock. The papillae are also controlled by neural signals from the brain, but this texture-changing process is even less understood than color-changing, Deravi said.

What makes octopuses so good at changing color? 

Many animals rely on camouflage, but octopuses are in a league of their own, largely because of the speed and accuracy with which they can transition between vastly different colors. "It's a fraction of a second," Deravi said. "I think the fastest [transitions] are under 100 milliseconds (0.1 seconds), which is faster than a blink of an eye."

In contrast, it can take chameleons several seconds to more than a minute to completely change color.  

Octopuses can make such rapid color changes because "their brain is deeply interconnected with the surface of the skin," Deravi said. "They have these really fast signaling mechanisms to be able to say 'turn on here' and 'turn off there' all over their body."

The main reason for this interconnectedness between brain and skin is that, unlike most animal brains, octopus brains are not confined to a single region (i.e the head). In addition to their donut-shaped brains, octopuses have "brain pockets," or nodes, all over their bodies and throughout their arms, Deravi said. Researchers believe that this enables individual octopus arms to have a mind of their own, which could play a role in color-changing. "However, trying to understand how this works is a whole other area of research," she added.

Octopuses also have more chromatophores than squids and cuttlefish per square inch of skin, Deravi said, which helps them to create super-high-resolution patterns compared with other cephalopods.

However, there is still one major unsolved mystery surrounding cephalopod camouflage: how they are so good at matching their skin color to their surroundings. Despite their ability to create a wide variety of different colors, a majority of octopuses and other cephalopods are actually color blind: Octopus eyes only have one type of photoreceptor, the cells convert light into neural signals, which means they can only detect differences in light intensity, according to a review paper published 2020 in the journal Frontiers in Physiology. (Human eyes have four types of photoreceptors.) 

One potential explanation is that octopus eyes are able to see color without photoreceptors. A 2016 study published in the journal Biophysics and Computational Biology hypothesized that there are additional receptor types in octopus eyes that are unfamiliar to us that could enable cephalopods to see colors in a different way than humans and other animals do.

There are also theories that light receptors in the skin could help octopuses match the colors around them. Previous studies have shown that octopus arms can react to changes in light intensity when octopuses cannot see. However, there is no evidence yet that this helps them to see colors.

Related: What color is the universe?

Understanding more about how octopuses change color is extremely challenging because researchers are not allowed to experiment on cephalopods while they are alive due to their intelligence, Deravi said. (Octopuses are considered intelligent because they can solve complex problems, use tools and feel pain.) In the U.K., it has been proposed that octopuses and squid should be listed as sentient beings.

Why do octopuses need to camouflage? 

Although the mechanics of octopus camouflage are still being uncovered, scientists have a much better understanding of why these awesome animals change color. 

"Octopuses have no external protection," Jennifer Mather, a psychologist at the University of Lethbridge in Canada who specializes in cephalopod behavior, told Live Science. To a predator, an octopus is an "unprotected package of protein," which means that "basically everybody in the ocean is out to get them," she said. 

"Evolutionarily speaking, the octopus had no choice," Mather said. "Without physical protection, it had to evolve ways to not be seen."

Some octopuses have developed other ways of hiding. For example, elusive glass octopuses have lost all their chromatophores and become almost completely transparent. However, for the species that rely on color-changing, adapting their hue is an inherent ability that is available to them from the moment they are born (as you can see in the video clip below of a hatching octopus at the Virginia Aquarium & Marine Science Center). 

There are other uses for camouflage too, such as hunting. "We tend to think of it as a defensive ability and I think it is more important as a defense," Mather said. "But that doesn't mean it's not useful to sneak up on something."

In addition to remaining unnoticed by their prey, octopuses can also use startling displays, where they break camouflage and stun their prey with drastic, rapid-fire color transitions before quickly trapping them, Mather said. 

Squid and cuttlefish use color displays on their skin to communicate between individuals. A few octopus species also do this — they can produce solid colored bands to attract mates or warn off rivals during reproduction — but this is much more basic than the communication displays in other cephalopods, Mather said. However, octopuses tend to be very antisocial animals and infrequently interact with other octopuses, so they have less need to communicate, she added.

That said, octopuses sometimes use their colors to communicate with other animals. For example, blue-ringed octopuses — four species of tiny yet extremely poisonous octopus — produce bright luminescent rings to warn animals to stay away from them to avoid being poisoned, according to a 2019 study published in the journal Molluscan Research. 

In 2019, scientists captured video footage of an octopus named Heidi changing colors in her sleep, which sparked speculation that octopuses may also change color when they dream. Researchers have identified human-like sleep cycles in octopuses, but not all researchers are convinced that the color changes can definitely be labeled as dreaming. "It's bad enough trying to figure out how people dream," Mather said. "It's absolutely impossible to figure out how octopuses dream." 

Although camouflage is an innate ability for most octopuses, researchers suspect that it is something they get much better at throughout their lifespan, which is normally around one to two years. "I think they get better when they get older," Mather said. "They're pretty good when they're young, but I think they get better at the nuances of it when they get older." They also learn to combine color-changing with other behaviors, such as hiding in crevices or changing body shape, over time, she added. 

Originally published on Live Science.

On April 30, beachgoers in Kommetjie, South Africa encountered a rare sight: a giant squid carcass glistening on the sand at Long Beach. 

"It was incredible to see," Alison Paulus, a Cape Town resident and founder of the wildlife conservation organization Volunteer and Explore, told Live Science in an email. "The body was around 2.2 meters [7.2 feet] alone, then with the tentacles and arms I'm sure it would have stretched to 3.5 meters [11.5 feet]."

Giant squids are among the most elusive animals on the planet. They live at ocean depths between 1,000 to 3,000 feet (300 to 1,000 m) and only rarely rise to the sea surface. For centuries, the only information scientists had about these creatures came from studying beached carcasses or remains found in the bellies of sperm whales — the first photos of a live giant squid weren’t captured until 2004, according to National Geographic. 

Spotting a giant squid on a South African beach is rare, though not unheard of. A beautifully preserved baby giant squid washed up near Cape Town in 2020, the Washington Post reported. Another adult specimen that washed ashore in the same area in 1992 was just over 30 feet (9 m) long, Devon Bowen, a digital manager at Two Oceans Aquarium in Cape Town, told the South African news site Independent Online (IOL).

Related: What's the difference between arms and tentacles?

This squid beached at night after sustaining injuries, possibly from an encounter with a commercial boat or fishing vessel. "We could see a long gash above its tentacles which we presume was from a boat propeller," Paulus said. Investigation by wildlife professionals revealed that the animal was a female. "I would say that she was most likely struck by a ship while she was at the sea surface," Jon Friedman, a wildlife officer from the Cape of Good Hope Society for the Prevention of Cruelty to Animals (SPCA), told IOL. 

Friedman estimated that the squid was around two years old when she died. Giant squids can live for up to five years and reach lengths of 43 feet (13 m), though most top out around 36 feet (11 m), according to Smithsonian. 

By the time SPCA officials reached the scene, local fishers had already removed the squid’s eyes, beak, and portions of its tentacles. Most of what remained of the carcass was then chopped up by the SPCA and thrown back into the sea, though officials sent some tissue samples off to Cape Town's Iziko South African Museum for DNA analysis. The museum currently holds the remains of 19 other giant squids, IOL reported. 

Paulus was disappointed that the body did not make it back to the museum, but said that her family was thrilled to see the squid while it was still intact. "I have two small sons who are crazy about wildlife, so we went down straight away to see," she said.

Originally published on Live Science.

On a recent deep dive into the twilight zone, a submersible hundreds of feet underwater filmed an unusual fruit-colored creature: a bright-red strawberry squid with eerie eyes — one small and black and the other large, bulbous and yellow.

Oblivious to the video camera, the strawberry squid (Histioteuthis heteropsis) cruised through its dark ocean home, occasionally twisting and curling its eight arms and two tentacles as its ghostly white fins rippled.

The sighting, which happened last month, wasn't totally unexpected, but it was still a pleasant surprise. "We see them often (maybe one dive in four), but they are far from abundant," Bruce Robison, a senior scientist with Monterey Bay Aquarium Research Institute (MBARI), told Live Science in an email. Robison, who wasn't part of the expedition that spotted this squid, leads the midwater ecology group at MBARI.

Researchers controlling a remotely operated vehicle (ROV) known as Doc Ricketts — an uncrewed submersible equipped with an ultra high-definition 4K resolution video — spotted the squid in Monterey Canyon off the coast of California. The canyon, home to diverse sea life, is nearly as deep as the Grand Canyon, making it one of the deepest submarine canyons on the West Coast of the U.S., according to MBARI.

Related: What's the difference between arms and tentacles?

The strawberry squid's mantle (the body, not including the eyes or appendages) can reach up to 5 inches (13 centimeters) long. The MBARI team tweeted about the encounter on March 23, saying, "Fresh from the deep!⁠ ⁠During a recent deep-sea dive, our team came across one of the most remarkable residents of the ocean's twilight zone: the strawberry squid (Histioteuthis heteropsis). We spotted this crimson cephalopod 725 meters (2,378 feet) deep in Monterey Canyon."

In a second tweet, the team noted that "The strawberry squid has one big eye and one small eye. Together, this unlikely pair helps the squid hunt for food in the ocean's twilight zone. The big left eye looks upward to spot shadows cast by prey in the dimly lit waters above."

Meanwhile, the squid's smaller right eye looks downward, searching for "flashes of bioluminescence produced by prey or predators lurking in the darker waters below," MBARI tweeted. Due to its differently-sized eyes, the strawberry squid is sometimes called the cockeyed squid.

Strawberry squid, however, aren't born cockeyed. Rather, H. heteropsis hatchlings are born with two identically-sized eyes. As they develop into juveniles, the left eye surges in size, and by adulthood the left eye can be more than double the size of the right eye, MBARI reported.

On land, vibrant colors make animals stand out, signaling prospective mates or broadcasting a warning about toxic defenses. But for the strawberry squid, its bright red color actually helps keep it hidden in the ocean depths. "Red light does not reach the deep sea," MBARI reported. "There, a crimson coloration actually appears black and helps the squid hide from the gaze of predators like sperm whales, dolphins, tunas, swordfish and sharks."

The strawberry squid doesn't get its name just from its red color; the cephalopod has dark spots on its red body that look like teensy strawberry seeds. These spots are actually photophores, or organs that produce light through a chemical reaction or through symbiotic glowing bacteria. The strawberry squid uses its photophores to counter-illuminate itself, meaning that it uses this light to match its surroundings as a form of camouflage. This helps the squid avoid predators that might otherwise see its dark visage in the dim twilight zone, Robison said.

Robison added that the squid's "fin rippling is generally for station-keeping or slow cruising. When it wants to move quickly, it uses jet propulsion out the siphon. It has soft canard-like fins on its lateral arms like some jet fighters do."

Originally published on Live Science.

Octopuses and vampire squid are famous for their eight arms, but one of the oldest relatives of the group that includes them didn't get the memo. This newly described creature, named Syllipsimopodi bideni after President Joe Biden, had a total of 10 arms when it was alive during the Carboniferous period about 328 million years ago, a new study finds.

The beastie was wee, with a mantle (the body, not including the eyes or arms) measuring 3 inches (7.7 centimeters) long, about the length of an adult's palm. It's the oldest record ever of a vampyropod — a group that includes octopuses and vampire squid (Vampyroteuthis infernalis) — pushing the group's existence back 82 million years. The new date supports evidence from molecular clock models that calculate, based on the expected rate of genetic mutations, when an animal likely evolved, the researchers said.

Some scientists, however, disagree with the assessment of the creature, pointing out that parts of the fossil are difficult to interpret and that the specimen might belong to a previously known species that was described in the late 1980s.

Related: Photos of the vampire squid from hell

The vampyropod fossil was discovered in Fergus County, Montana and donated to the Royal Ontario Museum in Canada in 1988. But it remained unexamined until recently, when two researchers determined that it was a newfound species. Its 10 arms appear to have suckers, which would be the oldest known suckers of any cephalopod, a group that includes octopuses, squid and nautiluses, the researchers said.

Some cephalopods, like squids, cuttlefish and bobtail squids, have 10 appendages — eight arms and two longer tentacles. "Octopuses and squid are both types of cephalopods, but they're very distantly related," said study lead author Christopher Whalen, a National Science Foundation postdoctoral fellow of paleontology hosted at the American Museum of Natural History (AMNH) in New York City and co-hosted by the Department of Earth & Planetary Sciences at Yale University.

So, it was surprising that this newly described creature had 10 arms. "It's the earliest ancestor of octopuses [and] things related to octopuses, but it looks a lot like a squid," Whalen told Live Science. 

Vampire squid — which are not squid or vampires, but are named for the cloak-like webbing between their arms — have eight arms and two thin filaments. It's thought that these filaments are vestigial arms, which octopuses lost completely. "However, all previously reported fossil vampyropods preserving the appendages only have eight arms, so this fossil is arguably the first confirmation of the idea that all cephalopods ancestrally possessed ten arms," Whalen said in a statement. 

"Prehensile-foot" Biden 

Whalen and study co-author Neil Landman, a curator emeritus in the AMNH's Division of Paleontology, named the critter "Syllipsimopodi" from the Greek words for prehensile and foot. "The name prehensile-foot is chosen because this is the oldest known cephalopod to develop suckers, allowing the arms, which are modifications of the molluscan foot, to better grasp prey and other objects," the researchers wrote in the study. The species name honors  Biden. "When we submitted the article, initially, it was actually just a few weeks after his inauguration," Whalen told Live Science. 

Related: What's the difference between arms and tentacles?

When S. bideni was alive, North America was a very different place. Montana, near the equator, was submerged under a tropical marine bay. Seasonal monsoons swept across the region. Just like fertilizer runoff can lead to algal blooms today, it's possible that heavy rainfall brought on by the monsoons led to a rapid influx of nutrients in the water, which in turn could have led to oxygen-poor waters; a pristine environment for fossilization, Whalen said.

S. bideni likely ate the ancient creatures whose fossilized remains were found nearby in the formation, including crustaceans, sponges, brachiopods and conulariids, which are thought to be related to jellyfish. "It probably had a lifestyle similar to modern nearshore squid," Whalen said.

Outside take

Although the fossil is in fairly good shape, some parts are difficult to interpret. For instance, the researchers noted that each arm has two rows of suckers, rather than just one as was thought to have been present in the early relatives of vampire squid and octopuses, said Michael Vecchione, an invertebrate zoologist at the Smithsonian's National Museum of Natural History in Washington, D.C., who specializes in living cephalopods and was not involved with the study. 

"That is really surprising to me," Vecchione told Live Science. It's possible that this interpretation isn't correct, he added. 

And it's not clear if this fossil represents a new genus, said Christian Klug, a curator at the University of Zurich's Palaeontological Museum and a professor at its Palaeontological Institute, who was not involved in the study. The new specimen looks an awful lot like Gordoniconus, an early cephalopod, co-described by Landman, in 1988, from the same place in Montana. 

"The proportions are identical, the size is identical [and the] conch shape is similar," Klug, who wrote about Gordoniconus in a 2019 study in the journal Communications Biology, told Live Science in an email. "Even if you accept that this is a different species: How likely is it to have two different species with almost identical shape in the same habitat?"

Whalen disagreed. "I also do not consider Syllipsimopodi to be similar to Gordoniconus in terms of proportion, size, or conch shape," he told Live Science in an email. Moreover, he noted "it is not in any way unusual for similar species to have overlapping ranges. For example, most people are used to seeing multiple species of similarly sized birds in their neighborhood; similarly, it would not be unusual to see multiple species of butterflies in the same garden at the same time."

The study was published online Tuesday (March 8) in the journal Nature Communications. 

Originally published on Live Science.

A team of researchers hunting for the wreck of a lost WWII destroyer ship in the Philippine Sea returned to land with another, perhaps even more exciting discovery: Video evidence of the deepest-swimming squid ever recorded.

Cruising just above the floor of the Philippine Trench at a staggering 20,300 feet (6,200 meters) below the surface, the young bigfin squid (family Magnapinnidae) became an instant record holder — blowing the previous champ, another bigfin squid swimming about 15,400 feet (4,700 m) below the Pacific Ocean, out of the water.

The researchers also recorded four cirrate octopuses — better known as dumbo octopuses for their fins that resemble elephant ears — around the same depth, the team wrote in a recent study. According to study co-author Michael Vecchione, this is just the second time that dumbos have been observed so deep, proving that previous observations of the floppy-finned cephalopods in the Java Trench were not just a fluke.

"This dive showed that multiple types of cephalopods can live in at least the upper parts of these really deep ocean trenches," Vecchione, a zoologist with the National Oceanic and Atmospheric Administration (NOAA) who is Curator of Cephalopods at the Smithsonian Institution in Washington D.C., told Live Science in an email.

The sightings also raise some questions, Vecchione added — like, "How do bigfin squids manage to live physiologically at depths ranging from 3,200 to 19,600 feet (1000 to 6000 m)," where atmospheric pressures can be up to 600 times greater than at the ocean's surface.

Researchers detected the bigfin in March 2021, while hunting for the wreck site of the USS Johnston — a U.S. Navy destroyer that sank in 1944 during the Battle of Leyte Gulf. Using the manned submersible DSV Limiting Factor (the same type of submersible that explorer Victor Vescovo used to descend to the bottom of the Mariana Trench in June 2020), the researchers filmed their dive to the bottom of the Philippine Trench, where they explored for more than four hours.

The team spotted the bigfin squid just above the ocean floor. Although the sub was hovering too high to image the squid in precise detail, the researchers were able to discern telltale features — such as the squid's extremely large back fins and its distinct swimming posture — that confirmed its identity. Because the squid's tentacles were relatively short, the researchers hypothesized that the deep-dwelling cephalopod was a juvenile.

The team published their findings Dec. 2, 2021 in the journal Marine Biology.

Originally published on Live Science.

A ghostly squid with huge, iridescent fins and funky, elbow-like bends in its tentacles is rarely seen, but scientists recently captured stunning footage of the elusive animal during an expedition in the Gulf of Mexico. 

To date, there have been fewer than 20 confirmed sightings of this deep-sea cephalopod, known as a bigfin squid (Magnapinna), and this recent sighting adds one more to the list, according to a statement from NOAA Ocean Exploration.

National Oceanic and Atmospheric Administration (NOAA) scientists spotted the elusive squid on their recent "Windows to the Deep 2021: Southeast ROV and Mapping expedition," during which the team explored poorly understood deepwater areas in the western Atlantic Ocean off the southeastern United States. While filming underwater near the West Florida Escarpment — a steep slope in the seafloor that separates the shallow, coastal waters from the deep Gulf of Mexico — the team noticed a set of spindly blue appendages drifting past their remotely operated vehicle (ROV).

Related: 8 crazy facts about octopuses 

In the footage, the camera turns to reveal the bigfin squid in all its glory, its eight arms and two tentacles strewn out behind it. The creature's large fins — which extend off the main portion of its body, called the mantle — ripple softly in the water, similar to how a stingray's fins flap. The see-through mantle holds the squid's organs, which appear light yellow and pink in the light of the ROV. 

Mike Vecchione, a research zoologist with the NOAA Fisheries National Systematics Laboratory and the Smithsonian's National Museum of Natural History, was onshore watching the ROV footage on a satellite feed as the bigfin squid came into view. He and Richard E. Young of the University of Hawaii first described the bigfin squid family, called Magnapinnidae, in 1998, according to a report in the South African Journal of Marine Science. Since then, three species of bigfin squid have been described, but there may be more bigfin squid species to discover, according to the NOAA statement.  

When the bigfin squid popped up on the ROV feed, Vecchione quickly called the vehicle operators, to share his knowledge of the animal, the statement says. "Magnapinna … all of their arms and tentacles have this extension on them, long, spaghetti-like extension," Vecchione can be heard saying in the NOAA video footage. "It's really difficult to tell the arms from the tentacles, which is very unusual for a squid." The bigfin squid holds all these appendages out from its body, creating those distinctive elbow-like dents that make its tentacles so recognizable.

The squid was seen swimming about 7,825 feet (2,385 meters) beneath the ocean surface, but in the past, bigfin squid have been spotted as deep as 15,535 feet (4,735 m) down, according to the statement. Members of the bigfin family are widely distributed throughout the world's deep ocean ecosystems, but it's unclear how many there are in total since the cephalopods are seen so rarely. Last year, scientists reported seeing five of the squid near the Great Australian Bight, a large bay in South Australia — the first time any bigfin squid had been spotted in Australian waters, Live Science previously reported.  

Originally published on Live Science.

Scientists mapping the seafloor in the Gulf of Aqaba, the "right antenna" part of the northern Red Sea, recently made two remarkable sightings almost simultaneously: a sunken shipwreck and a mysterious big squid zipping around it, according to the marine research organization OceanX.

After sending down a remotely operated vehicle (ROV), the OceanX team quickly identified the shipwreck — it was the Pella, a ferry that caught on fire and sank in November 2011. The squid, however, took longer to identify. But it made plenty of cameos; the crew used the ROV and submersibles to visit the wreck three times, and each time they saw a huge squid swimming by.

After consulting with Michael Vecchione, an invertebrate zoologist at the Smithsonian's National Museum of Natural History in Washington, D.C., the crew finally got an answer; the cephalopod was a purpleback flying squid (Sthenoteuthis oualaniensis), and a giant one at that.

"We got photobombed by the giant purpleback," Mattie Rodrigue, science program lead at OceanX, told Live Science. "I was joking it was a made-for-TV moment."

Related: Release the kraken! Giant squid photos

The purpleback flying squid run ins happened in October 2020, when OceanX's research vessel, the OceanXplorer, was on its maiden voyage mapping the seafloor of the northern Red Sea. The crew was in the Gulf of Aqaba's Neom region, and was steadily cataloguing the region's underwater ecosystem and bathymetry with technology aboard the ship, including multibeam sonars and deep-sea vehicles. 

Then, the ship's survey technician alerted Rodrigue that the multibeam sonars were picking up an anomaly about 328 feet (100 meters) long on the seafloor. Some crew members thought it was a large rock or coral reef, but others guessed it was a shipwreck. A subsequent investigation with the deep-sea vehicles confirmed it was the shipwreck of the Pella, which sank while en route to Nuweiba, Egypt, resulting in one passenger death.

As the ROV approached the shipwreck's bow at about 2,788 feet (850 m) below sea level, a large squid "came toward us then swerved away," Rodrigue said. 

The ROV has lasers that can help measure underwater objects, but the crew didn't turn them on in time. It's likely that the squid had a total body length of about 6 feet (2 m), said Vecchione, who spoke both with OceanX and Live Science. There are reports of mature female purpleback flying squid with mantles (the body or "hat-like" part of the squid) of up to 2.6 feet (82 centimeters), he said.

Purpleback flying squid come in five sizes, ranging from dwarf form to giant form, which this one likely was, Vecchione told Live Science. The squid's short and broad fins, as well as its body proportions, match those of a purpleback flying squid, and the Red Sea has a known population of giant form purpleback flying squid, he noted.

These squid are active predators that live in tropical and subtropical waters of the Pacific and Indian oceans, according to the Australian Museum. They live in the open ocean down to depths of about 3,280 feet (1,000 m), but swim frequently upward to shallower depths at night to feed. What's more, these muscular and speedy squid can cruise at speeds of 6.2 mph (10 km/h) with bursts of up to 22 mph (35 km/h), according to SeaLifeBase, an internationally maintained marine research site.

S. oualaniensis are harvested as bait for tuna in Japan and Taiwan, and they're also eaten by humans, "although the quality of the meat is relatively poor," according to the International Union for Conservation of Nature. 

It's unknown if purpleback flying squid frequently hang out around shipwrecks, but the sighting of this individual (or individuals, it was unclear if there was more than one) raises the question, Vecchione said. It's possible that shipwrecks attract fish, which squid prey on, he noted.

Spotting the squid was a memory she'll never forget, Rodrigue said.

"It was just so spectacular for me," Rodrigue said. "It was already going to be an exciting day because we were thinking that we were going to see a shipwreck … but we had absolutely no idea that we were going to encounter such a magnificent and large animal."

Originally published on Live Science.

Florida plays the unfortunate host to many invasive critters, from lionfish to Burmese pythons, but last week, officials announced that they had successfully eliminated a particularly slimy invader from the state: the formidable giant African land snail. 

The kicker is, giant African land snails (Lissachatina fulica) invaded Florida once before, meaning this is now the second time the troublesome pests have been expunged from the state. This time around, the effort cost $24 million and required 10 years of work, The Miami Herald reported. 

"There's still only one place on Earth where the giant African snail has been eradicated," Trevor Smith, director of the Florida Department of Agriculture and Consumer Services (FDACS) Division of Plant Industry, said at a news conference on Wednesday (Oct. 6). "It's right here, and now we've done it twice." 

"This truly is an exciting day for our state and for our country," Florida Agriculture Commissioner Nikki Fried said, according to The South Florida Sun-Sentinel.

Related: Survival of the grossest: 8 disgusting animal behaviors 

Why the elation? Giant African land snails can grow to be 8 inches (20.3 centimeters) long, and when they don't consume enough calcium from the soil, they begin munching through the stucco on houses instead, the Herald reported. The snails not only pose a threat to homes but also to Florida's agriculture industry, as they regularly gorge themselves on fruits and vegetables. And in the wake of their destruction, they squirt out a trail of smelly, stringy poop.

Some say the giant snails can give people and their pets meningitis, but that's technically true of all snails, Gizmodo reported in 2014. Snails can pick up a parasite named Angiostrongylus cantonensis from rat feces, if they consume it. And then if a dog then slurps up that snail in their backyard, or a human eats some snail meat stuck to an unwashed lettuce leaf, the parasite can sometimes reach the membranes of the brain and spinal cord, trigger an infection and cause swelling. Thankfully, the condition can be treated with antibiotics, but that doesn't make the thought of accidentally swallowing giant snail flesh any less gross.

The snails first arrived in South Florida in 1966, when a child brought three of the creatures to the area from Hawaii, where they're also invasive, the Sun-Sentinel reported. (The snails were initially imported as pets, and they may have also clung to cargo shipped from Africa, according to the National Invasive Species Information Center.) The child's grandmother reportedly released the snails into her backyard, and once released, the three snails multiplied and soon numbered in the thousands.

The state had quashed the invasion by 1975, but in 2011, a new wave of these snails suddenly surged. Smith said it's unclear exactly where the new snails came from, the Sun-Sentinel reported. That said, a recent state investigation suggested that, in 2010, a religious cult had snuck dozens of the snails into Florida from Nigeria for use in healing rituals, according to the Tampa Bay Times. But the snails may have also been imported unintentionally on cargo planes or ships, Fried said at the news conference.

Related: Weird animal facts

After being spotted in Douglas Park near Coral Gables, Florida, in 2011, the monstrous snails soon spread across the rest of Miami-Dade County and parts of Broward County just to the north, according to the Herald. Over the past 10 years, researchers with the U.S. Department of Agriculture (USDA) and the state of Florida have studied the snails' biology, to come up with strategies to kill the slimy creatures; they also kept track of reported outbreaks across the state. 

Since the start of the eradication effort, the team has collected and killed about 168,000 snails, the Herald reported.

The snails primarily come out at night and when it's raining, and they easily blend in with Florida foliage; when not out and about, the snails bury themselves under 6 to 8 inches (15 to 20 cm) of soil, making them even tougher to spot. So to find the pests, the state recruited two Labrador retrievers, Casie and Mellon, who trained for six months with the USDA to learn to sniff out the massive mollusks, according to the Herald. 

The most recent sighting of a giant African land snail took place in 2017, meaning the species can now be considered eradicated in the state of Florida. Fingers crossed, it'll stay that way.

Read more about the giant snail infestation in the South Florida Sun-Sentinel and Miami Herald.

Originally published on Live Science.

Giant squid (Architeuthis dux) are mysterious deep-sea predators with basketball-size eyes and tentacles that can stretch to 33 feet (10 meters) long. Giant squid are one of the world’s largest invertebrates and belong to an ancient group of mollusks called cephalopods, which also includes octopuses, cuttlefish and nautiluses. 

Giant squid sightings are likely what inspired tales of the ship-destroying Kraken from Scandinavian mythology. Real giant squid live at depths of at least 2,950 feet (900 m) below the ocean's surface and aren't known to attack ships.

Scientists still have much to learn about the lives of giant squid. Only twice have researchers been able to catch footage of these elusive giants in their natural environment — both times within the last 10 years, Live Science previously reported. Experts still aren't sure how many giant squid there are, or how many different species may exist, according to the American Museum of Natural History (AMNH) in New York.

Related: 500 million-year-old fossil is the granddaddy of all cephalopods

How big is a giant squid?

The biggest giant squid ever found was almost 43 feet (13 m) long, including its tentacles — that's about as long as a semi-trailer. However, scientists estimate that the species may be able to grow up to 66 feet (20 m) long, based on the size of giant squid beaks found in the stomachs of sperm whales (Physeter macrocephalus), which prey on giant squid, — according to the Smithsonian National Museum of Natural History. In many squid species, females are larger than males, and scientists believe the same is true for giant squid.  

Squid have eight arms and two tentacles, with spiked suckers that help grasp and pull prey toward their beaks. Squid beaks are made out of hard chitin, the same material as insect exoskeletons, with sharp edges that are perfect for chopping up prey into bite-size chunks, according to the AMNH.

Related: Stunningly intact giant squid washes ashore in South Africa

Giant squid vs colossal squid

Giant squid are massive, but they still have competition for the title of biggest ocean cephalopod. Colossal squid (Mesonychoteuthis hamiltoni) live in the Southern Ocean at depths of at least 3,280 feet (1000 m) and have larger and heavier bodies than giant squid, according to the Museum of New Zealand Te Papa Tongarewa. One of the few known colossal squid specimens, held at the Te Papa museum, weighs 992 pounds (450 kilograms), while giant squid are thought to only weigh up to about 606 pounds (275 kg). Colossal squid can reach lengths of 45 feet (14 m), but giant squid can grow even longer because of their two elongated tentacles, and may reach 66 feet, according to the Smithsonian.  

Where do giant squid live?

Giant squid can be found in oceans around the world at depths of at least 2,950 feet, but their exact geographic range is unknown. Giant squid are most often recorded in the North Atlantic and North Pacific, and near South Africa and New Zealand, according to the International Union for Conservation of Nature (IUCN). 

Some scientists believe that giant squid should be split into multiple different species, including separate species for populations in the North Atlantic, North Pacific and Southern Ocean. However, a 2013 study published in the Proceedings of the Royal Society B analyzed 43 giant squid samples collected from across their range and found little genetic diversity. This suggests giant squid are a single species and intermingle through migration.

Related: Giant squid all one big, happy family

Breeding

Giant squid are solitary, and scientists aren't sure how males find females to breed. Researchers hypothesized that because males and females probably only encounter each other occasionally, the females would collect and store sperm from multiple males. However, a female caught off the coast of Japan in 2020 only had sperm from a single male, suggesting giant squid may actually be monogamous, Live Science previously reported.  

Scientists aren't sure what squid mating even looks like. Experts assume that males place their sperm onto the female squid's arms, and suspect females may release eggs and hold them as they are fertilized in the water. The female then releases millions of fertilized eggs stuck together as an egg mass, according to the Smithsonian.

Baby squid are just 1 to 4 millimeters long when they hatch from their mother's eggs, and feed in the upper ocean at depths of about 650 feet (200 m), before descending deeper into the ocean when they mature, according to the Delaware Museum Of Natural History. Squid have short lifespans, and most species only live for one to three years. While scientists don't know exactly how long giant squid live, they believe it is no more than five years so they must grow very quickly, according to the Smithsonian.

What do giant squid eat?

Giant squid eat other, smaller squid species and hunt fish, including blue grenadier (Macruronus novaezelandiae), a torpedo-shaped deep-sea fish, according to the University of Michigan's Animal Diversity Web. 

Giant squid are themselves prey for sperm whales. But the cephalopods don't go down without a fight, and sperm whales are often found with sucker-shaped scars after hunting giant squid, according to the American Museum of Natural History.

Related: Beached sperm whale in Australia shows scars from tussle with a giant squid

The Kraken from Scandinavian mythology, likely inspired by giant squid sightings, was said to appear as small islands on the water to fool sailors into thinking it was land. As the story goes, the giant sea creature would then use its tentacles to pull ships and their crews beneath the waves. But humans are not part of the real giant squid's diet, and there's no reason for giant squid to attack ships.

Are giant squid endangered?

Giant squids are categorized as a species of least concern by the IUCN, which means they are not threatened with extinction. They have a wide geographic range and are less likely to be negatively impacted by human activity than many other species, as they live in the deep ocean. However, scientists don't know for sure how big the giant squid population is or what threats it could be facing.  

Additional resources

• Book about squid and other cephalopods: "Monarchs of the Sea: The Extraordinary 500-Million-Year History of Cephalopods" (The Experiment, 2020). 
• The American Museum of Natural History has a short video on YouTube describing encounters between giant squid and sperm whales. 
• BBC Earth offers more information about giant squid and their links to the mythological Kraken.  

A female of the world's largest squid — sometimes called the "kraken" after the mythological sea monster — that was caught off the coast of Japan apparently had just one amorous encounter in her lifetime. 

The female had sperm packets from just one male giant squid embedded in her body, which surprised researchers. Because giant squid are solitary creatures that probably run across potential mates only occasionally, scientists expected that females would opportunistically collect and store sperm from multiple males over time.

"We were almost confident that they are promiscuous," said Noritaka Hirohashi, a biologist at Shimane University in Japan. "We just wanted to know how many males are involved in copulation. So this is totally unexpected."

Related: Release the kraken! Giant squid photos 

Mysterious mating 

Hirohashi and his colleagues study reproduction and sperm biology in several squid species, but the most mysterious of all is Architeuthis dux, the giant squid. Rarely seen alive, the giant squid has a life cycle shrouded in deep ocean mystery. Video of living giant squid in their natural habitats has been captured only twice. The only thing researchers know about these mysterious creatures' mating habits is that female giant squid are sometimes found with large sperm packets known as spermatangia embedded in their muscles. Researchers writing in a 1997 paper in the journal Nature posited that male giant squid probably use their "muscular elongate penis" to inject the sperm packets into the females.

How sperm meets egg from there isn't entirely clear. It's possible that the female releases chemical cues that activate the sperm when she's ready to spawn, or perhaps she releases her eggs in such a way that they trail along the sperm packets as they leave her body. Squid females do have organs near the mouth called seminal receptacles, where some species storm sperm, and it's possible that in those species, the embedded sperm can travel over the skin to these receptacles. 

Knowing that witnessing two giant squid mating is highly unlikely, Hirohashi and his team developed a window into the process, using genetics. Examining squid specimens from fisheries and museum archives, they pinpointed some segments of the giant squid genome that would distinguish one set of squid DNA from another. Think of it like a squid paternity test: Any sperm packets found on a female can be tested to see if they came from multiple males and, if so, how many. 

The researchers are always on the lookout for sperm-spangled females. They send out flyers to local museums, fisheries and aquariums, asking them to alert the research lab if a giant squid specimen turns up. In February 2020, they got good news. 

"In this case, we found [a] Yahoo News [article] telling that the giant squid was caught," Hirohashi wrote in an email to Live Science. 

Saving sperm 

The specimen was a female, with a mantle, or main body, 5.25 feet (1.6 meters) long. It was missing a pair of tentacles and one eye but still weighed 257 pounds (116.6 kilograms). The squid had been caught in a fisher's net in Kyoto and was displayed at the Miyazu Energy Aquarium before being dissected. 

When Hirohashi's team examined the body, they found that the squid was just reaching maturity and that it had squiggly spermatangia 3.9 inches (10 centimeters) long embedded in five separate locations: three places on the squid's mantle, one by an arm and one on the head. Each location hosted at least 10 spermatangia. Some were near gashes that may have been caused by a mating male's beak. 

Genetic analysis of the spermatangia revealed that each and every one came from the same male. This was shocking to the research team; giant squid are often found bearing sperm packets, in a way that suggests that males aren't particularly picky. Spermatangia have been found on immature females, perhaps as a way for males to make their sperm available after the female matures, and even on males, perhaps because males are willing to try anything (or perhaps because they sometimes accidentally self-fertilize). All of the evidence pointed to a species that would mate first and ask questions later.

The specimen, of course, is just one female, so more research is needed to see if monogamy is the norm among giant squid females. It's possible that this female had simply only encountered one male before she was entangled in the net that ended her life, the researchers wrote in the September issue of the journal Deep Sea Research Part 1. Or perhaps it is typical for females to mate with just one male. The gashes might be part of the males' strategy for ensuring other males don't move in, perhaps by limiting a female's life span after mating so that she doesn't have time to collect more sperm. Or, the researchers speculated, the aggression and injuries could spur the females to mature and spawn so that the sperm is speedily fertilized. 

The next step is to study the spermatangia of more specimens, Hirohashi said. And researchers need to figure out how the stored sperm reaches the eggs, which are not deposited particularly close to the spermatangia. Researchers also need to figure out basically everything else about this elusive creature, including its life span, migration and habitats, he added. 

"Kids ask these questions at the aquarium, so we must answer," Hirohashi said. 

Originally published on Live Science

NASA is preparing to rocket around 5,000 tardigrades — those adorably pudgy "water bears —" and 128 glow-in-the-dark baby squid into space.

The animals are heading to the International Space Station (ISS) next week as part of SpaceX's 22nd cargo resupply mission.

SpaceX is set to launch the microscopic critters onboard a Falcon 9 rocket on June 3 1:29 p.m. EDT from Kennedy Space Center in Florida.

Related: 8 reasons why we love tardigrades

Tardigrades are tiny, just 0.04 inches (1 millimeter) long, and get their popular nickname from their tubby, bear-like appearance when viewed through a microscope. And these little guys are no pushovers — capable of surviving extreme radiation; pressures six times those found in the deepest parts of the ocean; and the total vacuum of space, making the microscopic animals much tougher than their ursine namesakes. In fact, the Israeli spacecraft Beresheet was carrying thousands of dehydrated tardigrades onboard when it crashed into the moon during a failed landing attempt on April 11, 2019. If any life-form could survive the crash, perhaps these creatures would, especially since they were in their dehydrated "tun" state from which they could be resuscitated.

It's these abilities that make the tardigrades such a useful research organism aboard the ISS, where astronauts hope to identify the specific genes responsible for the teensy animals' remarkable feats of adaptation to high stress environments. This should, in turn, give us some vital insights into the health impacts of long-duration space travel.

"Some of the things that tardigrades can survive include being dried out, being frozen and being heated up past the boiling point of water. They can survive thousands of times as much radiation as we can and they can go for days or weeks with little or no oxygen," Thomas Boothby, assistant professor of molecular biology at the University of Wyoming and principal investigator for the experiment, said in a news briefing. "They've been shown to survive and reproduce during spaceflight, and can even survive prolonged exposure to the vacuum of outer space."

For Boothby's study, astronauts will examine the molecular biology of the water bears to look for signs of any immediate and long-term adaptations to life in low-Earth orbit — which subjects daring space travelers to the rigors of zero gravity and increased radiation exposure. He hopes that the information gleaned from the creatures, set to arrive at the station in a semi-frozen state before being thawed out, will provide vital insights for future therapies that could protect astronauts' health during prolonged space missions.

A separate and parallel experiment also set to be delivered by the resupply mission will bring baby bobtail squid (Euprymna scolopes) to the station. The 0.12-inch-long (3 mm) squid have a special light-producing organ inside their bodies where bioluminescent bacteria give the squid their glow. The researchers of this experiment hope to investigate this symbiotic relationship between bacteria and squid to see how beneficial microbes interact with animal tissue in space.

"Animals, including humans, rely on our microbes to maintain a healthy digestive and immune system," Jamie Foster, a microbiologist at the University of Florida and principal investigator of the Understanding of Microgravity on Animal-Microbe Interactions (UMAMI) experiment, said in a statement. "We do not fully understand how spaceflight alters these beneficial interactions."

The squid are born without the bacteria, which they then acquire from the ocean around them, so the researchers are planning to add the bacteria to the squid as soon as the animals get thawed out at the ISS. This way, researchers can observe the squid as they establish symbiosis with the bacteria. By studying the molecules produced during the process, the researchers will be able to determine which genes the squid turned on and off to accomplish the feat in space. Knowing this could help humans better look after their gut and immune system microbiomes across long-distance space journeys.

Although the journey into space is a stressful one, the tardigrades, at least, have endured worse, having recently survived being shot from a high-speed gun. In that study, researchers found that tardigrades were able to survive impacts made at speeds of roughly 3,000 feet per second (900 meters per second), as Live Science previously reported.

Originally published on Live Science.

When a bizarre, white-polka-dotted blob the size of a person's palm washed ashore in North Carolina last December, rangers at Cape Lookout National Seashore weren't sure what to make of it. 

So the rangers turned to the public for identification help, posting a photo of the semitranslucent blob tangled in seaweed on their Facebook page on May 18. "It might be something like the egg sacks of a squid (but we aren't sure)," Cape Lookout rangers wrote in the post.

Turns out, their guess was spot-on: The blob is likely made up of the eggs of the Atlantic brief squid (Lolliguncula brevis), two biologists told Live Science. This squid, which lives in inlets and estuaries along parts of the Atlantic coasts of North and South America, is so small, it's "not the target of commercial fisheries, but they are abundant and important in marine ecosystems," said Ian Bartol, a professor in the Department of Biological Sciences at Old Dominion University in Virginia who was not involved with the blob's discovery.

Related: Under the sea: A squid album 

The blob's odd shape is officially known as an egg mass, but it has so many egg-filled sacks, researchers sometimes call such masses "mops," said Michael Vecchione, an invertebrate zoologist at the Smithsonian's National Museum of Natural History in Washington, D.C., who was not involved with the recently discovered blob. 

After mating, female brief squid lay about 30 eggs in a clear, gelatinous finger-shaped sack, which is usually about 1 inch (2.5 centimeters) long, Vecchione said. Then, the female secures the egg-filled sack to the seafloor in shallow waters — for instance, to oyster shells or clam shells — and other females often follow suit, attaching their egg-filled capsules to the same base, forming a mop.

It's unclear why females attach their egg capsules together, but the strategy might be protective. "If one capsule is attached and it doesn't drift away, chances are, that's a good place to attach them," Vecchione told Live Science. 

In the Chesapeake Bay, brief squid usually lay their eggs in September and October, Vecchione said. Farther south, the squid might lay their eggs later in the year, "so finding them in December in North Carolina doesn't really surprise me," he said.

It's possible that strong currents from a storm washed the egg mass ashore on Shackleford Banks, one of the barrier islands in Cape Lookout National Seashore, where they were found on Dec. 31, 2020, Karen Duggan, a park ranger at Cape Lookout National Seashore, told Live Science.

While getting washed ashore was definitely a game-ender for these eggs, there are surprisingly few predators that eat these mops in the ocean, Vecchione noted. For instance, some worms burrow into brief squid egg capsules, and in other squid species, crabs and fishes prey on egg masses, "but it's not very common," Vecchione said. "If they were easy to eat, then they would just be a smorgasbord for whoever comes along." It's possible that the gelatinous capsule has chemical defenses, and there's some evidence it has anti-microbial properties, he added. 

After the squid babies hatch from their eggs, however, it's another story. "As soon as they start hatching, they're fair game for a lot of things," including fish and other marine animals that eat plankton-size prey, Vecchione said. 

In adulthood, a brief squid's mantle (a measurement that doesn't include its head, eight arms or two tentacles) is usually no larger than 4.7 inches (12 cm) long, according to the South Carolina Department of Natural Resources. The squid has a few claims to fame. For one, it can live in waters with low salinity — as low as half that of regular seawater — which is rare among cephalopods, a group that includes squids, octopuses and nautiluses, Vecchione said. The brief squid can also tolerate "a broad range of temperatures and dissolved oxygen levels, allowing it to venture into estuaries where other squids cannot," Bartol added.

Brief squid also have rotating jets, so they can easily "swim both forward (arms first) and backward (tail first), and they are extremely maneuverable, as the jet and fins can be employed in a coordinated fashion," Bartol said. They can also change color, achieving optimal camouflage, he said.

A DNA analysis would be needed to formally identify this egg mop, as it is "kind of beat up from being washed ashore," but based on its size and place of discovery, it most likely belongs to a brief squid, Vecchione said. Other guesses include the longfin inshore squid (Doryteuthis pealeii) and the slender inshore squid (Doryteuthis plei), which also live in the region, according to an update Thursday (May 20) on the ranger's Facebook post.

Originally published on Live Science.

Architeuthis dux — the world's largest known squid — is surprisingly camera shy.

The elusive giant squid has wriggled its way into folklore for thousands of years, inspiring tales of fearsome krakens with bodies as large as islands. In reality, A. dux is a tad smaller than that, capable of growing to about 46 feet (14 meters) long —  about the length of a semi-trailer.

But despite their size, these cephalopods are almost never seen in the water; most observations of the behemoths come from dead or dying squids that wash up on shores or become ensnared in deep-sea trawling nets. That finally changed in 2012, when a team of marine scientists filmed a young A. dux in its natural habitat, about 2,000 feet (630 m) below the sea south of Japan.

Now, a study published online in the journal Deep Sea Research Part 1: Oceanographic Research Papers delves into why these giants of the deep are so elusive, and explains how a team of researchers was able to capture the first footage of A. dux in its natural habitat in 2012, and again in 2019 in the Gulf of Mexico.

According to the study authors (many of whom were present for the 2019 giant squid sighting), the creature's evasiveness is due, in part, to its enormous eyes.

Related: Release the kraken! Giant squid photos

Giant squids can live thousands of feet below the ocean's surface. Very little sunlight can penetrate this deep so to adapt, the giant squid evolved the largest eyes in the animal kingdom. Each of these cephalopods' peepers are about as large as a basketball — roughly three times the diameter of any other animal, Live Science previously reported.

These huge eyes not only help giant squids make their way around the deep, dark ocean, but probably also make them extra sensitive to the bright lights that marine researchers mount to their submersibles and underwater cameras, according to the study authors. That sensitivity could explain why giant squids are so hard to find in their natural habitats; by the time a research vehicle reaches a squid's swimming grounds, the squid has long since fled the craft's lights and vibrations.

To correct this over-illumination, the researchers involved in the 2012 and 2019 A. dux sightings turned down the lights on their submersible (named the Medusa). After reaching the desired depths, the Medusa turned off its lights and stopped moving, allowing creatures of the deep to come to it rather than actively navigating across the bottom of the sea. The team also illuminated its camera with a dim red light instead of the bright white lights typically used on expeditions like these, capitalizing on a natural deep-sea color-blindness.

"Many deep-sea species, including squid, have monochromatic visual systems that are adapted to blue [light] and blue bioluminescence rather than long wavelength red-light," the researchers wrote in the study. "Using red light may thus be a less obtrusive method for illuminating deep-sea species for videography."

The researchers also used the squids' attraction to blue light to their advantage, outfitting the Medusa with a custom lure that they called the E-Jelly. This small, spinning ring of neon blue lights sat on the end of an outstretched arm, mimicking the movement and glow of a bioluminescent jellyfish.

The lure worked, drawing A. dux out of the darkness in both 2012 and 2019. In fact, the giant squid spotted in the Gulf of Mexico was a little too convinced by the E-Jelly's display; as footage of the encounter shows, the giant squid tried to attack the Medusa's camera arm with its tentacles in the hope of taking home a nice jellyfish meal. (This assault enabled the team to measure the squid's tentacles, which appeared nearly 6 feet, or 1.8 m, long).

This strategy of combining low-light equipment with bioluminescent bait seems to be the most effective known method of tricking the giant squid out of hiding, the researchers concluded. That's a handy trick, as there is much to learn about the kraken's behavior that can only come to light in the darkness of its natural habitat.

Originally published on Live Science.