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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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.

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.

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.

As the seasons change, octopuses rewire their brains to adapt to fluctuating ocean temperatures, a new study finds. 

Octopuses and other cephalopods are cold-blooded, or ectothermic, meaning they cannot internally regulate their body temperature. As a result, they are vulnerable to external temperatures in the water, which can threaten the brain function of these exceptionally intelligent creatures if the water gets too cold or too hot. 

To prevent this, California two-spot octopuses (Octopus bimaculoides) edit their RNA — the messenger molecule between DNA and proteins — to produce different neural proteins in response to varying temperatures, according to the study, which was published Thursday (June 8) in the journal Cell. Led by researchers at the Marine Biological Laboratory in Woods Hole, Massachusetts, the study focuses on messenger RNA, which acts as a messenger for the instructions encoded in DNA and carries that transcribed genetic information to the protein-building factories, or ribosomes, in cells.

Related: Octopuses may be so terrifyingly smart because they share humans' genes for intelligence

During the study, scientists gathered 12 wild-caught California two-spot octopuses — a yellowish-brown species known for its two iridescent blue false eyes — and split them into two groups based on different test conditions: a warm tank with water that was 71 degrees Fahrenheit (22 degrees Celsius) and a cold tank with water that was 55 F (13 C). After several weeks, the researchers compared the RNA transcripts of the octopuses in the warm tanks to the ones in the cold. 

They expected to see changes in the RNA at only a few sites. Instead, they discovered changes at more than 20,000 of the 60,000 sites they looked at. And these RNA edits started happening within a matter of hours after the octopuses were exposed to new temperatures, the researchers found. 

"The beauty of RNA editing is that, on one hand, you change the genetic information and it's quite fluid, and on the other hand, you will keep the DNA intact," study co-author Eli Eisenberg, a genetics researcher at Tel Aviv University in Israel, told Live Science. "That's a nice thing that you can edit the RNA according to the needs of the present environment." 

For the next part of their study, they worked with researchers at the University of Michigan and Texas Tech University to determine whether these RNA changes actually affected protein structure. To do so, they compared the edited and unedited versions of two proteins in the octopuses that are crucial for nervous system function: kinesin, which are associated with cell membranes, and synaptotagmin, a calcium-binding protein. 

They found evidence confirming that temperature-driven changes in the RNA translated into structural changes in kinesin and synaptotagmin — and that these changes would also affect the proteins' function, likely in a way that makes the octopuses better adapted to the chilly or warm waters they are operating in. 

"One could say that [many of] the proteins that the octopus uses in the winter are not the same as the ones it uses in summer," Eisenberg said. A 2012 study showed differences in the RNA of different octopus species living in a variety of warm and cold environments, but this is the first research to show RNA editing happening in one octopus species in response to real-time changes in temperature, the researchers said. 

For many species, RNA editing has little or no effect on an individual because it happens in regions of the DNA that do not code for anything. For example, humans have millions of RNA editing sites, but only 3% of these affect proteins' structure. In octopuses, RNA editing affects the majority of their neural proteins, and now scientists know that these sophisticated cephalopods use this ability to acclimate to warm and chilly waters. 

The researchers also found evidence that the Verrill's two-spot octopus (Octopus bimaculatus), a closely related relative, also had temperature-sensitive RNA, suggesting that this phenomenon may be widespread among octopuses and squid.

"At the end of the day, we know very little about [cephalopods]," said Michael Kuba, an ecologist who specializes in cephalopods at the University of Naples in Italy and who was not involved in the study. "This paper is just an extremely important first step to really understand more how they deal with the environment," he told Live Science.

Eisenberg and his team are now working on further research to determine whether RNA editing is helping octopuses adapt to other environmental conditions, such as low-pH (acidic) or low-oxygen ("hypoxic") areas, which could become more common as climate change accelerates. 

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. 

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.

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.

If you're looking for bizarre creatures that defy explanation, there is no better place to look than the deep sea. Every year, researchers capture incredible footage of alien-looking animals and strange new species lurking in the deep, and this year was no different. Here is our list of the top 10 weirdest deep-sea creatures seen in 2021.

Blood-red jellyfish

In August, researchers with the National Oceanic and Atmospheric Administration (NOAA) announced the discovery of a brand-new and unnamed species of blood-red jellyfish. The dark red jelly likely belongs to the genus Poralia, according to the researchers.

They first spotted the new jelly on July 28 using a remotely operated vehicle (ROV) at a depth of around 2,300 feet (700 meters) just off the coast of Newport, Rhode Island. Other animals, including other cnidarians (jellyfish & corals), ctenophores (comb jellies), crustaceans and Actinopterygii (ray-finned fishes), were also seen on the dive.

Lots of deep-sea creatures have evolved a similar red color because red wavelengths of light do not penetrate into the deep ocean. This means that red animals appear black because there is no red light to reflect back toward potential predators. 

Read more: Mysterious blood-red jellyfish may be rare species unknown to science, researchers say

Elusive glass octopus

Also in August, researchers from the Schmidt Ocean Institute (SOI) released footage of an elusive glass octopus (Vitreledonella richardi) off the coast of the remote Phoenix Islands, an archipelago located more than 3,200 miles (5,100 km) northeast of Sydney, Australia.

The translucent cephalopod was originally discovered during a 34-day expedition of the Central Pacific Ocean onboard the SOI's research vessel Falkor. Onboard scientists  spotted the creature using the ROV SuBastian, which spent a total of 182 hours scanning the seafloor during the expedition.

Like other "glass" creatures, such as glass frogs and certain comb jellies, glass octopuses are almost completely transparent, with only their cylindrical eyes, optic nerve and digestive tract appearing opaque.

Read more: Elusive glass octopus spotted in the remote Pacific Ocean (Video)

Shape-shifting whalefish

The Monterey Bay Aquarium Research Institute (MBARI) released footage in August showing a bright orange, female whalefish (of the order Cetomimiformes) around 6,600 feet (2,013 m) deep offshore of Monterey Bay, California.

Very little is known about this bizarre fish because of the three drastically different appearances of the juveniles (tapetails), males (bignoses) and females (whalefish). The three forms look so different that scientists originally thought they were three different species. The shape-shifting transformation from juvenile to mature females is believed to be one of the most extreme among any vertebrates.

"Whalefish have rarely been seen alive in the deep, so many mysteries remain regarding these remarkable fish," the Monterey Bay Aquarium Research Institute tweeted. 

Read more: Shape-shifting fish that confounded scientists for 100 years spotted off California coast

'Emperor Dumbo'

In May, researchers reported the discovery of a brand new species of Dumbo octopus (Grimpteuthis imperator), nicknamed "Emperor Dumbo" by the researchers. 

Researchers discovered the adorable creature in 2016 when they accidentally dragged it to the surface in a net while aboard the German research vessel Sonne during an expedition of the Aleutian Islands in the Bering Sea. Dumbo octopus species can be identified by the umbrella-like webbing joining their tentacles and their cartoonishly ear-like fins that resemble the oversized ears on Disney's famous elephant.

"It was a really lucky find," Alexander Ziegler, a researcher at Friedrich Wilhelm University in Bonn, Germany, and chief scientist onboard the research vessel, told Live Science, "because we weren't really looking for it. Plus, the whole animal came to the surface intact."

Read more: All hail 'Emperor Dumbo,' the newest species of deep-dwelling octopus

Real-life SpongeBob and Patrick

In August, NOAA released a comical photo of the real-life counterparts of the cartoon best friends SpongeBob Squarepants and Patrick Star side-by-side on the seafloor.

The image of the square(ish) yellow sponge and five-pointed pink sea star were taken by an ROV on July 27, at a depth of 6,184 feet (1,885 m) during an expedition of the Retriever Seamount off the coast of New England. 

"The sponge is [in] the genus Hertwigia and the sea star is [in] the genus Chondraster," Christopher Mah, a marine biologist at Smithsonian's National Museum of Natural History who first made the comparison on Twitter, told Live Science. The exact species is unclear, and they could even be brand new to science, he added.

Read more: Real-life SpongeBob and Patrick found side by side on seafloor. But they likely don't get along.

Alien-like spindly squid

In November, NOAA scientists spotted a rare bigfin squid (of the genus Magnapinna) with an ROV during an expedition in the Gulf of Mexico. 

The ghostly squid has a very odd body plan with huge, iridescent fins and bizarre elbow-like bends in its tentacles. "All of their arms and tentacles have this long, spaghetti-like extension," Mike Vecchione, a research zoologist with the NOAA Fisheries National Systematics Laboratory, 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."

To date, there have been fewer than 20 confirmed sightings of this deep-sea cephalopod since it was first discovered in 1998. 

Read more: Eerie video captures elusive, alien-like squid gliding in the Gulf of Mexico

Giant phantom jellyfish

In November, MBARI released rare video footage of a giant phantom jellyfish (Stygiomedusa gigantea). Scientists operating an ROV at a depth of 3,200 feet (975 m) in Monterey Bay, California, spotted the massive jelly, with its 3.3-foot-wide (1 m) bell and 33-foot-long (10 m) ribbon-like arms.

Not much is known about phantom jellyfish, but scientists think it uses its arms, which stream like loose scarves in its wake, to ensnare unfortunate prey and winch them up to its mouth. The creature also propels itself through the pitch-black depths with periodic pulses from its faintly glowing bell.

"The giant phantom jelly was first collected in 1899. Since then, scientists have only encountered this animal about 100 times," MBARI said in a statement. Although it is rarely spotted, the jelly has been found in the depths of every major ocean in the world, except for the Arctic Ocean.

Read more: Giant 'phantom jellyfish' that eats with mouth-arms spotted off California coast

Photobombing squid

In October, researchers trying to map the seafloor of the Gulf of Aqaba in the Red Sea were shocked when they discovered a recent shipwreck from 2011. While trying to film the remains of the vessel, the team's ROV was continuously photobombed by a purpleback flying squid (Sthenoteuthis oualaniensis).

The shipwreck and squid were found at a depth of around 2,788 feet (850 m). The scientists from OceanX think it was a solitary squid, but it may have been more than one as it was hard to identify the cephalopod as it zoomed across the screen. The researchers also said the squid had a total body length of about 6 feet (2 m), which would be near the maximum size for the species. 

"It was just so spectacular for me," Mattie Rodrigue, science program lead at OceanX, told Live Science. "We had absolutely no idea that we were going to encounter such a magnificent and large animal."

Read more: Giant purpleblack flying squid photobombs crew investigating shipwreck

Sponge tracks on the seafloor

In April, a new study revealed the first evidence of deep-sea sponges crawling around on the seafloor, after researchers snapped photos of bizarre brown tracks left behind by the surprisingly mobile creatures in the Arctic.

The sponge trails were first photographed in 2016 by towed cameras behind a research vessel at Langseth Ridge — a poorly studied region of the Arctic Ocean that's permanently covered in sea ice — at a depth of between 2,300 and 3,300 feet (700 to 1,000 meters).

"The trails are made up of the spicules, or spines, which the sponge can grow," study co-author Autun Purser, a deep-sea ecologist at the Alfred Wegener Institute at the Helmholtz Center for Polar and Marine Research in Germany, told Live Science. "The sponge seems to expand along these spines, then contract to the new, moved position. During this process, some spines break off, forming the trails."

Read more: Arctic sponges crawl around the seafloor and leave bizarre brown trails to prove it

A see through skull

In December, MBARI researchers caught a rare glimpse of a barreleye fish (Macropinna microstoma). This bizarre fish has a translucent forehead, which it actually looks through using a pair of bulbous green eyes inside its head.

An ROV filmed the strange creature while cruising at a depth of about 2,132 feet (650 m) in the Monterey Submarine Canyon, one of the deepest submarine canyons on the Pacific coast. Extraordinarily, MBARI scientists have only ever spotted the species nine times previously, despite having completed more than 5,600 dives in the fish's habitat.

"The barreleye first appeared very small out in the blue distance, but I immediately knew what I was looking at. It couldn't be mistaken for anything else," Thomas Knowles, a senior aquarist at the Monterey Bay Aquarium, told Live Science.

Read more: New footage shows bizarre deep-sea fish that sees through its forehead

Originally published on Live Science.

A number of marine animals — including octopuses, squids, crabs and lobsters — will be recognized as sentient beings as part of a new law proposed by the U.K. government.

The Animal Welfare (Sentience) Bill was first proposed in May and is currently under review. The proposed law originally included all vertebrates, or animals with a backbone, but no invertebrates. However, on Nov. 19, the U.K. government announced that two invertebrate groups — cephalopod mollusks (octopuses, squids and cuttlefish) and decapod crustaceans (crabs, lobsters, shrimp and crayfish) — will now be included on the list of sentient beings, which means their welfare will have to be considered when future government decisions are made about them..

The driving force behind this addition was a new report published Nov. 19 by The London School of Economics and Political Science (LSE), which reviewed evidence from hundreds of scientific studies on these two invertebrate animal groups. 

Related: 8 crazy facts about octopuses

"After reviewing over 300 scientific studies, we concluded that cephalopod molluscs and decapod crustaceans should be regarded as sentient, and should therefore be included within the scope of animal welfare law," lead researcher Jonathan Birch, a philosopher of biological sciences at LSE, said in a statement. "I'm pleased to see the government implementing a central recommendation of my team's report."

Historically, it has been hard to prove sentience in animals because it is difficult to define.

"Sentience is the capacity to have feelings, such as feelings of pain, pleasure, hunger, thirst, warmth, joy, comfort and excitement," the researchers wrote in the report. However, pain reception is now widely considered to be the central criterion policymakers consider when drafting new legislation on animal welfare, they added.

The new study focused on evidence for different forms of pain reception, such as the possession of pain receptors and specific brain regions associated with pain, as well as behavioral experiments that show that these animals make choices to avoid painful or stressful scenarios. 

Being recognized as sentient means that the welfare of cephalopods and decapod crustaceans will have to be considered in any future decision-making processes, according to the U.K. government. "The Animal Welfare Sentience Bill provides a crucial assurance that animal wellbeing is rightly considered when developing new laws," Lord Zac Goldsmith, the U.K.'s animal welfare minister, said in the statement. "The science is now clear that decapods and cephalopods can feel pain, and therefore, it is only right they are covered by this vital piece of legislation." 

However, the new listing will not affect existing legislation surrounding these animals. This means several questionable practices — such as selling animals to untrained handlers, transporting animals in ice-cold water and boiling animals live without stunning them and other extreme slaughter methods remain legal even for sentient animals. 

The researchers are now calling for these practices to be outlawed. 

Boiling lobsters alive without stunning them is already illegal in the U.S., Switzerland, Norway, Austria and New Zealand, according to IFLScience.

Originally published on Live Science.

Explorers have captured video of the deepest-known octopus, revealing an adorably pudgy Dumbo octopus some 4.3 miles (6,957 meters) beneath the surface of the Indian Ocean swimming in what is called the hadal zone, where not even a drop of sunlight can penetrate.

The dumbo octopus (genus Grimpoteuthis), with its wee size and two relatively large fins that look like the eponymous Disney character's ears, is often called "the cutest octopus in the world," according to National Geographic. It's also one of the deepest-known octopuses, known to live more than 2 miles (3,200 m) below the ocean's surface.

The newfound creature — recorded more than a mile deeper than any octopus has ever been spotted before — and another Dumbo octopus dwelling 3.6 miles (5,760 m) below the surface were described in a new study, published May 26 in the journal Marine Biology.

Related: In Photos: Spooky Deep-Sea Creatures

These discoveries were made last April during dives to the Java Trench — the deepest part of the Indian Ocean — as part of the Five Deeps expedition, in which a team of explorers dove to the deepest part of all of the world's oceans in a submersible and deployed landers, as previously reported by Live Science.

Dumbo octopuses are  "cirrate" octopuses, meaning they have protrusions coming off their suckers called cirri, which have an unknown function, according to National Geographic. 

These observations "unequivocally" identify cirrate octopuses as members of the hadal community, the authors wrote in the paper. The hadal zone is the deepest part of the ocean — typically deeper than 3.73 miles (6,000 m). But because both octopuses were observed in the same area, it's difficult to know whether such octopuses live this deep globally or if this was "the result of chance encounter with an abnormally deep population," the authors wrote.

To live at such depths, these creatures' bodies would need to have somehow adapted to the extreme pressure of the deep sea, the chief scientist on the expedition, Alan Jamieson, who is also a senior lecturer at Newcastle University in the U.K. and the CEO of Armatus Oceanic, a deep-sea consultancy, told the BBC. "They'd have to do something clever inside their cells. If you imagine a cell is like a balloon — it's going to want to collapse under pressure. So, it will need some smart biochemistry to make sure it retains that sphere," he said.

The Indian Ocean is teeming with both familiar creatures such as starfish and sea cucumbers as well as unfamiliar ones. For instance, the Five Deeps explorers also captured a video of a strange gelatinous creature that looks like a balloon on a string, Live Science previously reported. 

• In Photos: The Wonders of the Deep Sea
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• Images: Cameron's Dive to Earth's Deepest Spot

Originally published on Live Science.

When an octopus coils one of its flexible arms around a rock or a bit of food, it's not because the animal's brain said, "Pick that up." Rather, the arm decides for itself what it's going to do next. For a person, that would be like having one's big toe call the shots about where they're going to walk.

But a cephalopod's nervous system isn't wired like a human's — or like the systems found in any other vertebrates, for that matter, where a central brain broadcasts marching orders to the rest of the body. Instead, octopus limbs are studded with concentrations of neurons called ganglia; these "arm brains" can therefore operate independently of the central brain.

In fact, scientists who recently visualized progressive movement in octopus arms discovered that the animal's central brain is hardly involved at all; they presented their findings June 26 at the 2019 Astrobiology Science Conference. [8 Crazy Facts About Octopuses]

The researchers used a camera and behavioral-tracking software to model how an octopus perceives and then processes information about its environment using its arms, Dominic Sivitilli, a graduate student in behavioral neuroscience and astrobiology at the University of Washington in Seattle, explained during the presentation.

"What we're looking at, more than what's been looked at in the past, is how sensory information is being integrated in this network while the animal is making complicated decisions," Sivitilli said in a statement.

An octopus's arm movement begins far away from the brain, triggered by sensors in a groping arm sucker feeling around on the seafloor or in an aquarium. Each sucker contains tens of thousands of chemical and mechanical receptors; to put that into perspective, a human fingertip holds just a few hundred mechanical receptors, Sivitilli said.

When an octopus touches something interesting, the "brain" in its arms processes the input and moves the signal along, telling the arm what to do next. Signals generated by one sucker are passed to its closest neighbor, activating arm muscles and generating a sweeping wave of motion that travels up the arm toward the body, the researchers discovered. While the arms are actively engaging with the environment — and with each other — the signal that reaches the animal's central brain is "highly abstracted" and not directly involved with arm interactions, Sivitilli explained.

Essentially, octopuses "outsource" computation about how to move their bodies, assigning those actions to local controls — ganglia — in each arm, rather than relying on the central brain to tell the arms what to do, Sivitilli said in the presentation.

"In a way, the octopus has sent its mind out into the environment to meet it halfway," he added.

But wait, you might be thinking — why are scientists talking about octopuses at an astrobiology conference? What does this have to do with extraterrestrial life? (And no, it's not because octopuses are really space aliens, as another group of researchers claimed in 2018.)

Octopuses are thought to be highly intelligent, yet their workarounds for perceiving and interacting with the world around them differ dramatically from techniques that evolved in intelligent vertebrates. Octopus cognition could therefore serve as an important alternative model for understanding intelligence, and it could prepare experts for recognizing unusual expressions of intelligent life that originated on other worlds, Sivitilli said in the statement.

"It gives us an understanding as to the diversity of cognition in the world," Sivitilli said. "And perhaps the universe."

• Photos: Ghostly Dumbo Octopus Dances In the Deep Sea
• In Photos: Amazing 'Octomom' Protects Eggs for 4.5 Years
• Octlantis: See Photos of Tight-Knit Gloomy Octopus Communities

Originally published on Live Science.

A rare sight

During the Oct. 23, 2018 dive of the ROV Hercules, part of the Nautilus exploration program, a cirrate octopod of the Grimpoteuthis species swam into view. Using the scaling lasers aboard the ROV, the research team estimated the animal to be less than 2 feet (60 centimeters) long. 

Related: Watch the video of the ghostly dumbo octopus

Graceful creature

Commonly known as the dumbo octopus, the animal was traveling at about 10,870 feet (3313 meters) below the surface of the ocean at the Davidson Seamount.

A frightful apparition

Almost ghostly in appearance, the cirrate octopus floated past the camera, using its wing-like fins to move.

Just keep swimming...

Flapping its fins, the nearly 2-foot long (61 centimeters) octopus maneuvered its way through the water inside the boundaries of the Monterey Bay National Marine Sanctuary.

An exciting capture

The sighting of this elegant animal took place on the first dive of the Nautilus expedition. Read more about the expedition at the Nautilus website.

Dancing and swimming

The expedition, scheduled to last from Oct. 21-31, 2018, aims to report on the life in the deep-water region southeast of Davidson Seamount, which is located off the coast of Monterey, California.

Revealing secrets

The octopod has also been called the umbrella octopus. The animal treated researchers to a view of its web, revealing each of its eight sucker-covered arms.

By any other name

The Grimpoteuthis has paired sets of finger-like muscular structures called cirri which span the entire length of the tentacles. The cirri help capture prey.

Showing off

The octopod gives the ROV a great view of its eight arms, web and cirri.

Tentacles everywhere

This particular creature was filmed in a section of the Davidson Seamount that was previously unexplored. It was one of many octopods spotted on the dive. See more images of the plethora of octopuses.

Teams of researchers

The Nautilus team includes scientists, ROV pilots, navigator, data logger, video engineer and science communicator. Each team rotation employs nine people.

Lots to do

The Nautilus crew has eight objectives for its 10-day mission that range from surveying the Davidson Seamount to collecting and analyze water and sea life samples.

Life in the deep

The dumbo octopus swims and drifts through out the field of view of a camera aboard the ROV Hercules.

Deep-sea life

The enchanting creature calmly flapped its two large fins as it cruised slowly through the dark.

Exploring the deep

The E/V Nautilus has been working with the Monterey Bay National Marine Sanctuary to send their underwater remotely-operated vehicles (ROVs) to unexplored regions of the Davidson Seamount, about 80 miles (129 kilometers) off the coast of Monterey, California. The researchers discovered an abundance of octopuses in the area — an "Octopalooza," if you will. Read more about the expedition at the Nautilus website.

Brooding eggs

During one of its dives, the Nautilus' ROV spotted several octopuses huddled in the rocks. Look closely and you can see the shiny white eggs beneath those tentacles.

Dedicated mothers

Octopus mothers nestle in the rocks to lay their eggs. They wrap their arms around their heads and sit on top of the eggs to keep them safe and clean.

Rivers of octopuses

The ROV cruised over hundreds of octopus moms lined up in the rocks. The researchers identified them as Muusoctopus robustus.

Neatly tucked in

The discovery of the octopus nursery was unprecedented in this region. A similar but smaller aggregation has been found once before off the coast of Costa Rica. Read more about the giant gathering of octopus mothers.

Not alone

There were numerous other creatures in the octopus nursery, too, such as sea anemones, snails and shrimp.

Eight-legged wonders

In a different spot, this beautiful dark-red octopus kept its large eyes on the ROV.

Color shifers

The octopus didn't stay dark-red for long. Many species of octopus can change the color and even the texture of their skin.

A diverse group

There are more than 200 species of octopus and they come in a wide variety of sizes — from the 16-foot (5 meters) Pacific octopus (Enteroctopus dofleini) to the tiny pygmy octopus (Octopus wolfi) that's smaller than an inch. [Check out this tiny baby octopus.]

No dummies here

Octopuses are highly intelligent creatures. They're capable of solving complex puzzles and have been known to escape their enclosures.

Advanced dexterity

Their arms have a mind of their own. About two-thirds of an octopus's neurons are in their arms, according to the Ocean Exploration Trust.

A ghostly friend

The Nautilus' ROV Hercules also captured video of this graceful dumbo octopus (Grimpoteuthis sp.). [Watch the video of the ghostly dumbo octopus. ]

Umbrella of tentacles

The graceful dumbo octopus twirled and opened up its umbrella of tentacles, revealing eight rows of suckers.

Graceful glider

The team used scaling lasers on the ROV to estimate that this particular deep-sea ghost was just under 2 feet (60 cm) long, which is a little larger than most dumbo octopuses.

The incredible video captured of the seemingly friendly, little eight-legged ghost elicited squeals of delight and wonder from the team behind the camera on the E/V Nautilus, who immediately identified the animal as a rare dumbo octopus (Grimpoteuthis sp.).

"Oh, and the world loves a dumbo," one of the team members said Oct. 23 when the video was captured. [Gallery: Cutest Creatures from Deep Sea Canyons]

The enchanting creature calmly flapped its two large fins as it cruised slowly through the dark. After a few seconds, the octopus opened up its tentacles in an elegant display, revealing its umbrella of legs with eight rows of suckers.

"Yeah, he's a show-off," one team member said. "You're going to be famous," said another. Both were true statements, of course, because who can resist such a charming cephalopod? 

The gentle dumbo octopus, also known as an umbrella octopus, is named for its ear-like fins that resemble the Disney character Dumbo's oversize elephant ears. There are 13 species of dumbo octopuses, and most of them live at depths of below 9,800 feet (3,000 meters). They're one of the rarest species of octopus, so catching a glimpse like this is pretty extraordinary.

The team used scaling lasers on the ROV to estimate that this particular deep-sea ghost was just under 2 feet (60 centimeters) long, which is a little larger than most dumbo octopuses.

The research ship Nautilus is funded and operated by the Ocean Exploration Trust, a nonprofit organization founded in 2008 by Robert Ballard. An ocean explorer and National Geographic explorer in residence, Ballard is best known for finding the sunken remains of the RMS Titanic.

The goal of the E/V Nautilus is purely to conduct scientific exploration of the ocean floor. The group is now in its fourth year of ocean exploration.

For the past couple of weeks, the Nautilus has been working with the Monterey Bay National Marine Sanctuary to explore an inactive, deep-sea volcanic mountain range called the Davidson Seamount. The area is about 80 miles (129 kilometers) southwest of Monterey, California, and has been nicknamed the "oasis of the deep," as it hosts a wide array of deep-sea corals, sponges and numerous other invertebrates. But a few spots in the region remain unexplored, and that's where the Nautilus has been sending its ROVs.

Only a few days after spotting the graceful dumbo octopus, Hercules came across a massive octopus nesting ground, where more than a thousand deep-sea octopuses huddled in the rocks with their eggs.

Find more incredible photos and videos of the octapalooza at Davidson Seamount on the Nautilus Live webpage.

Originally published on Live Science. 

Scientists didn't know what kind of octopus egg they'd plucked from the bottom of the sea until the shell started to hatch — then, they saw the elephant ears.

The adorable cephalopod hatchling, which you can see in a new video taken by researchers on a National Oceanic and Atmospheric Administration (NOAA) expedition, is known as a Dumbo octopus (genus Grimpoteuthis). Named after Disney's flying elephant, Dumbo octopi are easily distinguished by the floppy, ear-like fins popping out of their heads, which they use to swim around the deep sea.

The video, which accompanies a new paper published today (Feb. 19) in the journal Current Biology, shows a freshly hatched Dumbo octopus swimming for the first time in a bucket of water aboard the NOAA research vessel. [8 Crazy Facts About Octopuses]

The wee hatchling's mantle — the bulbous shell above its tentacles, where most of its internal organs are located — measured just 0.5 inches (13 millimeters), the researchers wrote. But besides being teensy, the hatchling's anatomy appeared to be fully formed right out of the egg.

Subsequent magnetic resonance imaging (MRI) scans and a three-dimensional reconstruction of the baby octopus revealed that it was born with everything it needed to immediately swim with its fins, sense its environment and capture prey (which Dumbo octopi swallow whole). It was even born with a large internal yolk sac, researchers said, which contained enough nutrients to keep the hatchling alive for several days while it learned to catch its first meal.

"The virtual exploration and 3D reconstruction of the internal anatomy of this deep-sea creature was particularly revealing," study author Alexander Ziegler, a researcher at Rheinische Friedrich-Wilhelms-Universität Bonn in Germany, said in a statement. "I was impressed by the complexity of the central nervous system and the relative size of fins and the internal shell."

Researchers used a remotely operated vehicle (ROV) to collect the hatchling's egg from a coral reef in the mid-Atlantic, about 1.2 miles (2,000 meters) below the ocean's surface. Dumbo octopods are typically found living just above the seafloor at depths of 1.8 miles to 2.5 miles (3,000 to 4,000 m) below the sea surface, though some have been seen as deep as 4.3 miles (7,000 m), according to the Aquarium of the Pacific.

Video evidence of mature Dumbo octopi reveals that they're also pretty slick dancers.

Originally published on Live Science.

Enter Octlantis

The gloomy octopus (Octopus tetricus) is usually a solitary species. But at two sites now, researchers have discovered gloomy octopuses living in high densities and interacting with one another in Jervis Bay in Australia. From mating to signaling to evicting one another from dens, these octopuses were found living in what the scientists have nicknamed an Octlantis. Here's a look at one of the close-knit cephalopod sites. 

Related: Read the full story on Octlantis

Cephalopod community

Finding a second site where the gloomy octopuses were interacting suggests such social behaviors are more widespread among octopuses than previously believed, the researchers said.

Diving for octopus

The divers visited the site in Jervis Bay, Australia, on eight different days between Dec. 17, 2016, and Jan. 14, 2017. They counted as few as 10 and as many as 15 individual octopuses at the site. And those octopuses in a cluster of dens "were often within arms' reach of one another," the researchers noted in their paper, published online Sept. 1, 0217, in the journal Marine and Freshwater Behaviour and Physiology.

Outa here

In one video taken by the researchers, an octopus approached a cluster of dens, reached into one and evicted the resident of that den.

Male suckers

The evictor and evictee both showed oversized suckers on their first two pairs of arms, suggesting they were both males, the researchers said.

And again

The evicted octopus fled to a cluster of dens at the east end of Octlantis and settled into a den there. Just minutes later, the researchers saw that Octopus "D" swam to that part of the site, right up to the den of the evictee and again evicted that octopus from its den.

Shark sighting

A similar interaction played out in video recorded when the researchers weren't present at the site. In that scenario, an octopus (labeled "D") evicted another (labeled "C") from its den and then spent 40 minutes guarding the den and keeping other octopuses from entering or occupying it.

Because octopus D was busy guarding this stolen den, he was away from his own den for some time. "In addition to substantial time investment, energy expenditure, and risk of injury, activity outside of their dens also exposes octopuses to risks from predators," they wrote. And sure enough, a wobbegong shark (shown here) arrived at the site after the interactions between octopus D and others.

Eviction notice

Another look at a male gloomy octopus evicting another from its den in Octlantis. [Read the full story on Octlantis]

Octopuses are famous for their bizarre bodies, quick thinking and mischievous personalities. There are more than 300 species of octopus that scientists know about, and likely many more we have yet to discover.

The largest known octopus is the giant Pacific octopus, which weighs as much as 600 pounds (270 kilograms) and grows as long as 30 feet (9 meters) across, according to the Marine Conservation Society. That's as long as a bus! The smallest octopus, the star-sucker pygmy octopus, is tiny in comparison, weighing less than 0.04 ounces (1 gram) and growing less than 1 inch (2.5 centimeters) long — shorter than the width of a quarter.

An octopus has eight arms that can all move independently of each other. Octopuses use their arms for a variety of tasks, such as to catch prey, use tools, walk along the ocean floor and even taste.

5 fun facts about octopuses

• Octopuses have a parrot-like beak, which is the only hard part of their body.
• The plural of octopus is "octopuses" or "octopi," according to Merriam-Webster. Some people also say "octopodes."
• Octopuses can change color, but it takes a lot of energy. They burn more calories changing color than humans do on a 25-minute run.
• Octopuses can rewire their brains to adapt to different ocean temperatures.
• All octopuses are venomous. Blue-ringed octopuses are among the most toxic animals on Earth, and have a neurotoxin that can kill humans.

Everything you need to know about octopuses

Octopus pictures

Discover more about octopuses

—How do octopuses change color?

—See extremely rare photos of alien-looking '7-arm octopus' spotted near Washington coast

—What's the difference between arms and tentacles?

A vibrant and striking photo of an octopus spreading its tentacles in an Indian Ocean tide pool won diver Gabriel Barathieu the title of Underwater Photographer of the Year (UPY) 2017.

In the winning photo, titled "Dancing Octopus," Barathieu used a wide-angle lens to capture the colorful cephalopod in shallow water, "which makes the octopus look huge," he said in a statement.

His portrait of the graceful predator was selected from approximately 4,500 images of underwater animals and scenes submitted by photographers representing 67 countries. Over just two days, a panel of three judges pared down the entries to 100 finalists, according to UPY jury chair Peter Rowlands, publisher of Underwater Photography magazine. [Surreal Shots: See the Winning Underwater Photos]  

"From my own point of view, I have been captivated not only by the winning images but also by the stories behind how those images were achieved," Rowlands said in the statement.

UPY celebrates underwater photography in natural and human-made settings, selecting four annual winners: Underwater Photographer of the Year, British Underwater Photographer of the Year, Up and Coming Underwater Photographer of the Year, and Most Promising British Underwater Photographer.

Outstanding photographs are awarded in 10 categories, including Macro, Wide Angle, and Behavior.

To capture the octopus photo — taken in springtime in the Mayotte archipelago between the coast of Mozambique and the island of Madagascar — Barathieu waited for the tide in the lagoon to go out. He wanted the water to be as shallow as possible "so that the octopus would fill the water column," he said in the statement.

In the first-place photo for the Macro category, a delicately translucent mantis shrimp larva stands out starkly against a deep black background — "like a sci-fi encounter in outer space," Rowlands said. Photographed by diver So Yat Wai, the larva's red eyes appear to be fixed on a tiny object in the water in front of it — possibly its next meal, Wai suggested in a statement.

Even decaying inanimate objects can appear mysterious and beautiful when glimpsed through the lens of an underwater photographer, as seen in the Wrecks category, which features boats, planes and other vehicles in varying stages of disintegration on the ocean bottom.

The winning Wrecks photo shows a visually arresting image of the Louilla, a ship that ran aground and was abandoned at the Gordon Reef in the Straits of Tiran near Egypt in 1981, photographed by diver Csaba Tökölyi in a way that the wreck is visible both above and below the ocean surface.

"Beneath her lies a pile of her anchor chains, giving the form of a whale," Tökölyi said in a statement.

The full list of the 2017 contest winners appears on the UPY website.

Original article on Live Science.

In the dark of night, an enterprising octopus named Inky snuck out of his tank at the National Aquarium of New Zealand and made an eight-armed dash for freedom.

After squeezing through the top of his tank, Inky slithered across the deserted aquarium floor and shimmied down a 6-inch-wide (15 centimeters) drainpipe that — luckily for him — led directly to the sea.

Inky's breakout came as no surprise to marine biologists who study these natural escapologists. "They are curious, inquisitive animals," said Roger Hanlon, a senior scientist at the Marine Biological Laboratory in Woods Hole, Massachusetts. "They forage hundreds of meters per day looking for food and mates and different shelters. This is an ambulatory animal, so the idea that they would want to move outside their tank in an aquarium is not at all surprising."  [8 Crazy Facts About Octopuses]

Octopuses have escaped their enclosures before, said Hanlon. From unscrewing tightly capped jars to crawling out of their tanks, these marine animals have fascinated both scientists and the public with their skills.

Underwater, octopuses have keen eyesight, but even after climbing out of a tank, they can use the suckers on their arms for touch and taste, as well as for suction. Each arm has about 200 suckers and thousands of neurons per sucker, according to Hanlon. And together, these suckers act as a well-coordinated unit, allowing an octopus to "walk" across the seafloor, through the shallow water between tide pools and even on aquarium floors.

Although octopuses can survive out of water for a few minutes, they don't like really dry floors, said Hanlon. If Inky had found a wet trail on the aquarium floor, he probably would have taken that route instead to keep the cuticles on his suckers moist. "It's extremely important for octopuses to protect their complicated suckers," said Hanlon. "If it walks across a dry floor, that cuticle gets pulled off, and it's a bit like getting your fingernail pulled off."

But in the ocean, octopuses like crawling around, and go into and out of holes all of the time, said Christine Huffard, a cephalopod biologist at the Monterey Bay Aquarium Research Institute in Moss Landing, California. The animals have no bones in their bodies, so they can fit through small cracks, or even spaces in an aquarium lid. And they have developed a whole host of other adaptations so they can avoid predators, including the ability to camouflage rapidly, change their appearance to look like a jigsaw puzzle gone awry and blend into the ocean waves by matching the speed of the waves. [Video: Watch a Clever Octopus Make Like a Flatfish]

"Octopuses are highly evolved and specialized," Hanlon told Live Science. "They have the largest, most complex brain of any invertebrate animals on Earth." These complex brains allow octopuses to process information and make decisions about which tricks to deploy to escape predation (or an aquarium). They can also form mental maps recording the locations of their dens even after a long forage over several hours and many habitat types, said Hanlon.

It is part of an evolutionary response to the complex and dangerous coral reef environment the animals live in, he said, because diving marine mammals and birds like to snack on octopuses, as do sharks, eels and meat-eating fish like barracudas and groupers.

Inky, who was a common New Zealand octopus, probably used these brainy skills to sneak out of the National Aquarium in Napier, New Zealand, said aquarium manager Rob Yarrall. And although Inky left behind another octopus that shared the same tank, octopuses are solitary creatures, so Inky is unlikely to be missed — though his former tank-mate could still decide to make a go for it, too.

Follow Knvul Sheikh on Twitter @KnvulS. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

In September, a remotely operated vehicle on a dive off Hawaii had a run-in of sorts with a curious and shiny octopus squid. Though scientists first thought the graceful swimmer was a whiplash squid, they later accurately identified it as the Dana octopus squid. Here's a look at what the ROV's cameras picked up while face-to-face with the arm-y animal. 

Lights, action!

The Dana octopus squid, Taningia danae is 3 to 7 feet (1 to 2 meters) in length and was flashing the lights that tip two of its arms, when the ROV called Deep Discoverer caught the animal on video. (Photo Credit: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana)

Hello, squid

The ROV was diving to investigate two cone features along an extension of an underwater mountain chain called the Hutchinson Seamount when the big squid " attached itself to the back of ROV Deep Discoverer (D2) and hung out there for several minutes before coming around to the front of the vehicle," according to a log by scientists aboard the Okeanos Explorer vessel (which operated the vehicle). (Photo Credit: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana)

Flexible fins

To steer itself through the water, the octopus squid furls and flaps the flexible fins that extend from its mantle. (Photo Credit: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana)

Nice lips

The feature on its face (the underside of its mantle) that appears to be a red mouth is actually a siphon. The squid expels water from through this siphon from a mantle cavity behind the eyes. The squirting water propels the squid backward. (Photo Credit: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana)

Naming a squid

The Dana octopus squid, shown here off Hawaii, got its name in 1932 after a specimen of the squid was caught off the Cape Verde Islands by individuals aboard the Danish research vessel Dana, according to The Cephalopod Page, run by the University of Hawaii. The genus name, Taningia, honors Danish fisheries biologist AageVedel Tåning (1890-1958). (Photo Credit: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana)

Gotcha

Here, the Dana octopus squid attaches itself to the ROV Deep Discoverer. (Photo Credit: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana)

8 arms

T. danae is part of the Octopoteuthidae family of eight-armed squid. Though the juveniles sport two tentacles in addition to their eight arms, by the time they grow up those tentacles are either greatly reduced or completely gone, according to The Cephalopod Page. (Photo Credit: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana)

Flashing spotlights

The squid's lemon-size photophores (seen tipping two of its arms) are considered the largest known light-producing organs of any animal, said Mike Vecchione, director of the NOAA National Systematics Laboratory at the Smithsonian and a curator of cephalopods at the National Museum of Natural History in Washington, D.C. The organs are covered with "lids" that can be opened to show off the bioluminescent glow. (Photo Credit: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana)

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Often considered the smartest invertebrates (animals without backbones) on the planet, octopuses can use tools, unscrew jar lids and tightly control their body color to match their surroundings. They use this sharp intelligence especially in situations of survival — including when they are trying to avoid getting eaten by their hungry mates.

Octopuses come in all shapes and sizes and inhabit diverse regions of the ocean. There are about 100 different species of octopuses in the genus Octopus, and at least another 150 species in other genera, said Jennifer Mather, a cephalopod expert at the University of Lethbridge in Canada. Scientists have witnessed the mating behavior of only about a dozen species, she added.

The marine animals have very short lives, generally lasting only a few years long and sometimes as short as 6 months. They spend their youth alone, eating and growing before reaching sexual maturity. [8 Crazy Facts About Octopuses]

"Then they become sexually mature, metabolize their muscles to make eggs and sperm and begin to mate," Mather told Live Science.

Love displays

It's unclear how mature male and female octopuses find each other in the vast ocean. Males appear to devote a lot time searching for mates, while females typically become less active in adulthood and possibly draw males to them using chemical cues.

Because they're solitary animals, octopuses aren't exactly picky with their mates. "Females don't usually refuse males," Mather said. However, that's not to say the clever cephalopods have no courtship rituals to entice potential mates.

Male common octopuses (Octopus Vulgaris), for instance, are known to rear up and display several large suckers on the underside of their tentacles to identify themselves as male, but only if approaching a larger female, which may decide to attack and eat them. They will also spread themselves out to appear large, and turn a dark or pale coloration.

A male day octopus (O. Cyanea), on the other hand, will stand tall and tower over his potential mate, while turning pale — as he approaches a female, he'll flash a distinctive pattern of black stripes across his body.

Abdopus aculeatushas one of the most complex sexual behaviors among octopuses. In this species, a male will guard a female from other males, typically while staying in a den in tentacle's reach of the female's den. If another male comes by, he pushes and grapples with his competition, a fight that may end in a fatality.

To identify their sex, male A. aculeatus keep a black- and white-stripe pattern on their bodies while in the presence of a female and during aggressive encounters, and females remain camouflaged. Some "sneaker" males use these telltale signals to their advantage by matching their body color to the female's — this allows them to creep past a guarding male and mate with the female secretively.

A dangerous game

Mating for males is a dangerous game due to the female's penchant for cannibalism. To avoid getting eaten, they'll often mate from a distance or after mounting the back of a female's mantle — positions that give them extra time to escape should their (usually larger) mate turn violent.

Unlike females, "males have a modified third right arm called a hectocotylus, which has a sperm groove down it and a specialized tip," Mather said. To mate, a male will insert his hectocotylus into the female's mantle cavity and deposit spermatophores (sperm packets). This process may take up to several hours, depending on the species.

In some genera, particularly those in which males are far smaller than females, such as Argonauta (argonauts, or paper nautiluses) and Tremoctopus (blanket octopuses), males have a detachable hectocotylus, which they break off after inserting it into the female's mantle.

Females store their spermtophores until they're ready to lay their eggs. Typically, males die within months after mating, while females watch over their eggs until they hatch and then die shortly after. In one deep-sea species, Graneledone boreopacifica, females may brood over their eggs for up to 4.5 years without ever leaving to eat.

The larger Pacific striped octopus, which doesn't yet have a formal name, appears to break the octopus mating rules. In this odd social species, mating takes place mouth-to-mouth and sucker-to-sucker — and these females don't practice cannibalism. What's more, the females can lay multiple clutches of eggs before dying.

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A new video has captured a man's epic undersea battle — with a giant octopus.

A scuba diver, 56-year-old Warren Murray, and his diving buddy, 34-year-old David Malvestuto, were exploring a cove off Carmel, Calif., when they spotted an elusive 8-foot-long (2.4 meters) giant Pacific Octopus that blended in with the surroundings. Murray took out his camera to capture the rare sight when the undersea giant snaked a tentacle out, wrapped it around the camera, and tried to yank it away.

Murray managed to snap the flash, and the light-startled beast swam away. Malvestuto managed to capture the wrestling match on camera, reported The Jacksonville Observer. This type of octopus can grow to about 30 feet (9 m) with its tentacles extended, the Observer noted.

Follow Tia Ghose on Twitter and Google+. Follow Live Science @livescience, Facebook & Google+. 

Cool brain facts

This Behind the Scenes article was provided to LiveScience in partnership with the National Science Foundation.

The human brain is the most complex and least understood biological structure in the known universe.

To advance brain science, President Obama in April 2012 announced the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative, which is co-led by the National Science Foundation (NSF).

BRAIN, NSF invested in fundamental brain research that produced amazing discoveries related to humans and animals. Here are 10 recent findings from NSF-funded brain research, running the gamut from insights about the brains of dinosaurs and octopuses to discoveries involving Alzheimer's, brain-controlled machines and more.

Surprise! Some types of wrinkles are good

Our human brain is relatively large for our body size and more wrinkled than the brains of other animals. Brain size and wrinkle numbers correlate with intelligence across species.

The outer layer of the human brain is covered by wrinkles, and the more of them the better. Why? Because these wrinkles increase the surface area available for neurons (the functional units of information processing) without increasing head size, which is good for women during childbirth. Human brain wrinkles are thought to be almost as hereditary as human height.

Elizabeth Atkinson of Washington University in St. Louis recently identified chromosome segments and genes that correlate with wrinkle numbers in about 1,000 baboons, which are genetically similar to humans. The next step: pinpointing exactly where in these genetic regions folding patterns originate, which would provide insights into the evolution of the human brain.

Dinosaurs: Not big and dumb, after all — just big?

A new map of a generalized dinosaur brain suggests the possible existence of a cerebrum, a brain part that controls complex cognitive behaviors in mammals. Although scientists don't know what functions dinosaur cerebrums may have controlled, their existence would suggest that dinosaurs may have performed more complex behaviors than previously believed — such as forming social groups and possibly communicating.

The map is based on inferences from the genetics and organization of crocodile and bird brains. Crocodiles pre-date many dinosaurs and are their closest living relatives, while birds post-date dinosaurs.

Because crocodiles, dinosaurs and birds form an evolutionary chain, scientists believe that these animals' brain structures shared important traits, and so key features of dinosaur brains may be deduced from crocodile and bird brains.

The brain map is also based on fossilized dinosaur skull cavities, which yield implications about the shape of dinosaur brains. Such evidence provides the best clues to the dinosaur brain in the absence of any known fossilized brain tissue from dinosaurs. The dinosaur brain map was created by a team led by Erich Jarvis of Duke University.

A possible explanation for Einstein's intelligence

Studies of Einstein's brain conducted in the 1980s revealed that Einstein had an unusually large number of brain cells, called glia, in his cerebral cortex, and that one type of his glia was unusually large and complexly shaped. Though lacking statistical significance, these studies helped generate interest in glia.

Glia had long been dismissed as connective tissue that doesn't contribute to learning and memory, as do neurons. This idea had become entrenched because glia don't generate electrical signals — considered to be the core of brain function — as do neurons.

Harder evidence of the glia's influence on intelligence includes a 2013 study involving the injection of human glia into the brains of newborn mice. As adults, the injected mice became faster learners than control subjects.

Also, two recent papers promoted a new consensus among leading brain scientists about the importance of glia — which may even promote learning. How? Brain imaging indicates that when people learn new skills, from juggling to playing computer games, the structure of specific brain regions changes. These changes may be due to the glia's formation of myelin, a fatty insulating substance, around axons (nerve fibers), which speeds the transmission of electrical signals from axons.

In mind-computer melds, brains still important

A brain/computer connection is a partnership: A human brain tells a machine what to do and the machine responds accordingly.

When this type of partnership works, a brain and machine may accomplish amazing things together. For example, in experiments, students flew model helicopters using their thoughts via special head caps that were equipped with sensors that decoded their brain activity. In similar setups, people with physical disabilities used a robotic arm to grab cups of coffee.

But humans often struggle to control their mechanical partners, partly because it takes significant time to learn how to do so. One way to reduce this training time may be to improve mind/body awareness — as indicated by a recent study led by Bin He, Director of the Center for Neuroengineering at the University of Minnesota. His results showed that that training in mind/body awareness through practices such as yoga or meditation enabled people to master a brain-computer interface almost five times faster than untrained people did.

Even as brain/computer connections are made more user-friendly, He's results underscore the continuing importance of the human element for these systems.

Scientists may be able to predict when you'll be primed for risky business

Recent advances in brain imaging technology may allow researchers to predict whether someone will make a safe or a risky financial decision based on certain types of brain activity prior to deciding.

According to Brian Knutson and Charlene C. Wu of Stanford University, people who expect to win big show increased activity in certain brain regions, including the nucleus accumbens, which is associated with reward and pleasure, whereas those who expect to lose show increased activity in the anterior insula, which is linked to anxiety and disgust.

The more money at stake, the more activity is seen in those regions. But while more activity in the nucleus accumbens encouraged risk-taking, more activity in the anterior insula reduced risk taking.

These findings imply that when people are more excited, they will take bigger risks. In fact, long-shot wins (like potential lottery wins) powerfully increased both excitement and nucleus accumbens activity, encouraging people to take risks, even as they strayed from the choices of a "rational" person.

Studying people's brains while they consider their risk-taking options reveals insights about why people make certain financial decisions. These findings have implications for individual patterns of risk-taking — such as saving for a 401K — as well as for basic theories that describe group behavior.

Cell-based therapy may ultimately help beat back brain cancers

Brain tumors are the second-leading cause of U.S. cancer-related deaths, with 70,000 diagnoses of this invariably deadly disease made annually.

Now, Stefan Bossmann and Deryl Troyer of Kansas State University are working to improve a type of promising cell therapy that has yet to be used successfully. The researchers' therapy would work by collecting a cancer patient's blood; refurbishing selected white blood cells with "cargo holds" or closed cavities that would be filled with anticancer drugs; and then re-injecting the patient's blood to deliver drugs directly to tumors.

Previous efforts to develop this type of cell therapy produced weak, leaky medicinal cavities that killed carrier cells, not tumors. But the researchers are improving these cavities by developing a new type of material for them that forms something akin to a self-assembling artificial bubble — designed to be selectively absorbed by the right type of white blood cells, remain strong enough to hold medicine and naturally self-destruct upon reaching tumors.

Cell therapy delivers significantly more anticancer drugs to tumors than does conventional chemotherapy and nanotherapy, without damaging the body's immune system.

With preliminary experiments in mice competed, the therapy will soon be used to specifically target mice tumors for the first time, with the hope that this therapy will ultimately be able to be successfully used on human brain tumors.

The octopus: The eyes have it — literally

The octopus is a successful predator, partly because it has excellent eyesight — the best of any invertebrate — which enables it to visually zero in and focus on its prey.

What's more, each of the octopus's eight agile, boneless arms is equipped with about 44 million nerve cells almost 10 percent of all of its neurons). These arm neurons are connected to the animal's brain.

When an octopus spots a tasty-looking fish, resulting visual information travels from the animal's eye to its brain. This information then travels through its arm neurons to help these soft-bodied contortionists determine how to snatch the meal.

Conversely, tactile information, such as the feel of a crab's rough shell, travels back through the octopus's arm to its brain's learning and memory centers to help these clever animals improve their hunting skills.

A team led by Clifton Ragsale of the University of Chicago is the first to use modern molecular techniques to study how the octopus's unique nervous system processes visual information, and if the octopus's processing system significantly differs from that of vertebrates. If such differences are found, they may reveal alternative ways for brains to process visual information and learn. Resulting insights may yield important applications for robotics and image detection devices.

Birds' responses to climate change: It's all in their heads

Different bird species use different cues to determine when to migrate and to reproduce. Whether any particular species will be able to adjust its timing of such activities fast enough to keep up with climate change may partly depend on which cues it uses.

To varying degrees, all bird species use day length as a cue. They measure daylight and anticipate seasonal changes via light-activated receptors located deep in their brains. The light penetrates their skulls without even necessarily passing through their eyes.

Because day length is unaffected by climate change, some long-distance migrators, such as the pied-flycatcher, whose main migratory cue is day length, have maintained fairly consistent arrival times at their spring breeding grounds. Yet, spring temperatures now tend to increase earlier in the year because of climate change. So such migrators now tend to arrive at their breeding grounds late relative to premature springs — and therefore now miss insect population peaks upon which they previously feasted. With less to eat, such migrators are now producing fewer chicks, which may cause population declines.

Some bird species augment day length cues for migrating and/or breeding with other cues, like temperature changes, which are probably also processed in their brains. Changes in the timing of the migratory activities of some temperature-sensitive bird species correlate with climate change-related temperature changes.

But most studies of the processing of day length by birds have addressed only males. Now Nicole Perfito of the University of California, Berkeley is studying how females of two bird species process day length and other cues that influence the timing of egg laying — an important factor in their potential responses to climate change.

Still wanted: A complete parts list of the human brain

The human brain has about 100 billion neurons. But scientists don't yet have a complete inventory of the many types of brain cells that exist and their functions. They also don't understand how electrical and chemical signals from neurons produce thoughts, behaviors and actions.

Without such knowledge, scientists cannot yet explain how traumatic injuries and neurodegenerative diseases impair brain function or should be treated. By comparison, imagine a mechanic trying to fix a car engine without a complete parts list and/or an understanding of how its engine runs!

Yet, new types of brain cells are often being identified, partly because of new brain imaging techniques that can zoom in on the brain to reveal increasing detail, just as Google Maps can zoom in on neighborhoods.

But without a universal classification system, cell types that have already been discovered may have been named and classified according to inconsistent criteria, such as shape, function or location. Therefore, some newly "discovered" cell types may really be rediscovered, renamed cell types.

To standardize the naming of neurons and create a universally accepted inventory of neuron types, Edward Boyden of MIT and others are working with the Allen Institute for Brain Science to create the first comprehensive database of types of brain cells.

Designer antibodies may ultimately help fight Alzheimer's

Antibodies, which are proteins traditionally made by the body's immune system in response to invaders, are already established allies in our fight against the flu virus and other harmful entities. Now, they are being engineered to treat and possibly protect us against disease-linked proteins, such as those associated with Alzheimer's disease.

Such engineering requires designing antibodies that have extreme targeting capabilities so that they can be directed to go where and do exactly what is needed. Antibodies used for therapeutic or experimental reasons are usually taken from immunized animals or enormous antibody libraries. So it's difficult to custom-order them.

Peter Tessier of Rensselaer Polytechnic Institute in Troy, New York is working to engineer antibodies that have precise properties. By placing DNA sequences of the target protein within antibodies, Tessier may design antibodies to bind to select proteins, such as beta-amyloid plaques, a protein linked with Alzheimer's. Further research may lead to the development of antibodies that recognize and remove toxic particles before they do harm.

Editor's Note: The researchers depicted in Behind the Scenes articles have been supported by the National Science Foundation, the federal agency charged with funding basic research and across all fields of science and engineering. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation. See the Behind the Scenes Archive.

A teeny octopus hatchling still cradled in its egg, a bubblegum pink coral and a bug-eyed bobtail squid are among the darling creatures spied by a deep-ocean explorer plying canyons off the northeastern coast of the United States.

The canyons carved into the continental slope near Nantucket, Mass., range from about 1,800 to 7,000 feet deep (550 to 2,100 meters). Currents carry sediments and nutrients into the clefts, supporting a higher diversity of marine life than the surrounding habitats, according to a National Oceanic and Atmospheric Administration (NOAA) statement. The continental slope marks the steep break between the shallow shelf near the shore and the deep ocean.

The little-explored canyons are the focus of a deep-diving expedition by NOAA's Okeanos Explorer, a research ship with a new remotely operated vehicle (ROV). Researchers are documenting the canyon geology and diverse marine communities, which help support local fisheries. [Gallery: Cutest Creatures from the Deep Sea Canyons]

The sea creatures spotted by the expedition include more than 25 deep-sea coral species, wary mother cephalopods (the taxonomic class that includes octopuses and squid) and an eel attack caught on video.

"Each canyon appeared to host different biological communities — even different depths within the same canyon would reveal different types of coral and sponge ecosystems," Tim Shank, a deep-sea biologist from Woods Hole Oceanographic Institution in Woods Hole, Mass., said in a statement. "As with any new deep-sea region we explore, we observed many suspected new species and remarkable range extensions of known species," he said.

The ship's sonar also discovered the northernmost methane-gas seeps detected to date off the U.S. Atlantic Coast. The ROV snapped photos of methane hydrates, the icy lattices that trap methane gas inside cages of frozen water.

Email Becky Oskin or follow her @beckyoskin. Follow us @livescience, Facebook & Google+. Original article on LiveScience.com.

Warm ocean currents off the coast of Southern California delivered a surprise to a couple of squid fishermen this past weekend.

A female argonaut ― an octopus also called a paper nautilus ― turned up in their bait box, The Daily Breeze reported Oct. 16. The men recognized the rare find and turned it over to the Cabrillo Marine Aquarium, said Kiersten Darrow, the aquarium's research curator.

Argonauts live near the surface of the open ocean, unlike most other octopuses, which live near the bottom. The argonauts secrete thin, translucent shells that hold pockets of air, helping them float. Their normal range is the warm water along the equator, especially near Indonesia and the Philippines, Darrow told OurAmazingPlanet.

"I've never seen anything quite like this," she said of the California find.

The silvery, baseball-size animal the fishermen caught has eight tentacles, big eyes and the color-changing abilities characteristic of an octopus. Its size means it's probably a full-grown adult, Darrow said.

In one of the aquarium's Jacuzzi-sized tanks, the octopus is now exploring its surroundings, flashing gold when it sees an overhead light or purple when it's in darker water, Darrow said.

"A couple of times, it's reached out its tentacles and explored around the tank, touching the different walls, especially if we have food sitting on the bottom of the tank. It seems like it's smelling the water," she said.

When the argonaut first arrived at the aquarium, it lay at the bottom of its tank without moving. Aquarium staff gently nudged it to surface so it could suck in some air. "Sure enough, it was able to float in water after that," Darrow said.

The octopus is on a diet of shrimp and fish. The aquarium staff hopes to see it exhibit hunting behaviors. If it does, they'll prepare to release the argonaut back into the wild.

"Our first goal was to try to make it better," Darrow said. "We'd like to release it, but we don't want to release it if it's sinking to the bottom. If the animal can hunt food, then we know it has good chance of survival."

Reach Becky Oskin at boskin@techmedianetwork.com. Follow her on Twitter @beckyoskin. Follow OurAmazingPlanet on Twitter @OAPlanet. We're also on Facebook and Google+.

The chilly waters of the Arctic and Antarctic Oceans are enough to slow anyone down. But octopi that have relocated to these areas play tricks with their genetic material to keep moving.

Cold temperatures slow us down because all molecules move slower in colder temperatures, including those proteins that send "movement" messages along nerve cells. To compensate, one species of chilly-water octopus change, or "edit," intermediate protein-making molecules — called RNA — a short-term solution that allows greater flexibility than if they were to actually alter DNA, called genetic mutations.

While scientists have known that RNA editing exists and that it can change how certain channels in the body open and close (and in turn how long it takes to send messages along nerves), they hadn't seen it happen in response to an environmental cue, specifically temperature, study researcher

of the University of Puerto Rico, told LiveScience.

Chilly cephalopods

The researchers compared two species of octopus. Pareledone species were collected at the Antarctic research facility, McMurdo Station, where the waters average 35.2 degrees Fahrenheit (1.8 degrees Celsius). The other species, Octopus vulgaris, came from the waters off of Puerto Rico, which are usually about 86 degrees Fahrenheit (30 degrees Celsius).

They analyzed the genes that make up the electricity-conducting ion channels that regulate when a brain cell (or neuron) sends a message. The researchers found little difference in the signals between the two species; to compensate for the temperature-based slowdown, Antarctic and tropical octopi used their very similar genes in different ways.

"What really surprised us, when we cloned [looked at the code of the] the genes, they were virtually identical between the Antarctic and the tropical octopus, after millions of years apart in very different temperatures," Rosenthal said. "It isn't the differences in the genes that drive adaptations in the cold. The organisms are editing the RNAs in way that adapts to the cold."

Editing RNA

So even though the genes were the same, the researchers found evidence that the RNAs of the cold-water octopus were changed before they were made into proteins. RNA is the intermediate form of DNA that actually produces proteins that tell the body how to function.

When expressed without editing, the cold water ion channels open about 14 times slower and close 60 times slower in cold water compared with warm waters. When turned on, this particular RNA editing changed the way these channels worked and allowed the octopus to compensate for the harsh physical conditions, keeping its nerve signals moving relatively quickly even in chilly waters.

"From the standpoint of the organism … it gives you good options because you can decide to change protein function now or you don't want to. You don't have to stick to exactly what your gene says," Rosenthal said. "To the more casual observer it would seem like this is a lot to go through for the organism, but this allows org to have a graded response, not just one response or another."

This editing is one example of how differences between species go much further than their genetic code alone. Even similar-looking genes can end up making big differences in different species. RNA editing is less prevalent in vertebrates and mammals; there are about 30 to 40 known editing sites in humans.

The study was published today (Jan. 5) in the journal Science.

You can follow LiveScience staff writer Jennifer Welsh on Twitter @microbelover. Follow LiveScience for the latest in science news and discoveries on Twitter @livescienceand on Facebook.

The National Zoo's new Giant Pacific octopus is one curious creature. Now it has a name to match its personality: Pandora.

The octopus had a chance to pick its own name by choosing one of four names dropped into its tank. When the octopus didn't touch one of the objects in its tank containing the names, a blindfolded keeper used a net to pick the name randomly. The other names, submitted by the finalists in the Washington Post's KidsPost naming contest, were Mirage, Inkling and Odysseus.

"I'm very excited because they chose my name and it'll be a good name for this octopus," said Trinity Kimberly, age 10, from Sterling, Va. "They described the octopus as curious and Pandora means curious."

Keepers placed each name on a placard name tag and dropped the name tags in plastic balls into the octopus tank, providing the octopus with its first so-called enrichment items since the charismatic cephalopod arrived at the National Zoo in November. Zookeepers use enrichment items to stoke the curiosity of octopuses, which are very intelligent animals and natural explorers.

The new octopus will ultimately help the zoo learn more about octopod mysteries, such as how to encourage the animals' unique behaviors. Staff and volunteers will introduce enrichment items and observe whether the octopus explores the objects, which is a natural behavior. The KidsPost contest received more than 300 entries from kids ages 5 to 15 over two weeks, and the keepers narrowed that list down to the four finalists.

"We are overwhelmed by the response from children not only in the D.C. community, but from all over the world who entered this contest," said Alan Peters, curator of the zoo's invertebrate exhibit. "The staff selected names that were followed by clever descriptions that highlighted the unique characteristics and mysterious nature of our octopus. We were particularly thrilled with many of the entries because they continued with our theme of Greek mythological names and the zoo's use of the Greek form of the word octopus, which is octopuses."

The new octopus is about 1.5 years old, which means that it is still too early to determine the animal's sex. It will take time for the octopus to mature before the zoo can do so.

The giant Pacific octopus is the largest octopus species in the world. The octopuses emerge from eggs only a little larger than a grain of rice, but as adults can weigh hundreds of pounds, with an arm span of more than 12 feet (3.6 meters). Zookeepers anticipate that the new octopus will grow to be more than 10 times its current size over the next year. Octopuses, like cuttlefish and squid, can change their skin texture and color as a defense, making them masters of camouflage.

Follow OurAmazingPlanet for the latest in Earth science and exploration news on Twitter @OAPlanet and on Facebook.

By peering into the genes of the mimic octopus, which has the mind-boggling ability to shift its color and shape to impersonate anything from sea snakes to stingrays, scientists are now uncovering the evolutionary steps it took to become a master of disguise.

The eight-legged "oracle" known as Paul the Octopus recently made international headlines with its amazingly lucky forecasts during the World Cup. But the most jaw-dropping octopus might actually be the Indonesian mimic octopus (Thaumoctopus mimicus).

This shape-shifter can alter its colors, contort its body and undulate to imitate the appearance of giant crabs, seashells, flatfish, brittle stars and other critters. For instance, to mimic a lionfish, it adopts striped patterns on its skin and juts its arms out like the fish's many venomous spines; to mimic a deadly sea snake, it hides its body in a hole, leaving only two arms out, which it moves together to impersonate the serpent. [Video – Watch the Mimic Octopus in Action.]

"The intelligence that is implied by their ability to mimic different kinds of sea animals depending on the circumstances is astonishing," researcher Healy Hamilton, evolutionary biologist and director of the Center of Applied Biodiversity Informatics at the California Academy of Sciences, told LiveScience.

How to make a master of disguise

Like its relatives, the mimic octopus can hide from hungry predators by blending into its background. So scientists have wondered why the multitalented species instead often chooses to mimic dangerous creatures with eye-catching color patterns, a daredevil maneuver thought to help it confuse or scare away threats.

"The close relatives of T. mimicus use drab colors and camouflage quite successfully to hide from predators," said researcher Christine Huffard, marine conservation priorities advisor and behavioral ecologist at Conservation International Indonesia. "Why does T. mimicus instead draw attention to itself, and repeatedly abandon the camouflage abilities it inherited from its ancestors in favor of a bold new pattern?"

To find out more about how this master of disguise developed its abilities over time, the researchers analyzed DNA sequences of the mimic octopus and more than 35 of its relatives.

"DNA sequencing is a very powerful tool to really identify who is most closely related to who in animals whose morphology is highly variable like octopuses," Hamilton said.

The researchers next compared physical and behavioral traits among the relatives, some of which are also capable of mimicking flatfish, such as the Atlantic longarm octopus (Macrotritopus defilippi). By seeing which traits many of the octopuses possessed, they could determine which traits evolved first, and by analyzing which traits only close relatives of the mimic octopus shared, they could tell which developed later.

Results showed the ancestors of T. mimicus first evolved the use of striking displays of dark and light bands, employed to surprise predators if camouflage failed, potentially buying them time to escape. Next, they figured out how to flatten their arms and head and swim like a flatfish, and also developed the long arms that facilitate this motion. Finally, the mimic octopus began displaying bold color patterns while impersonating a flatfish — both at rest and during daily forays away from its den.

"Somehow, through natural selection, being conspicuous has allowed T. mimicus to survive and reproduce more successfully than some of its less showy ancestors, and eventually evolve into its own lineage," Huffard said.

Risky evolutionary step

In evolutionary terms, the last step the mimic octopus took represented an extremely risky shift in defense strategy. The researchers suggest this trick could fool predators into thinking the octopus is a toxic flatfish such as the peacock sole or the zebra sole. It may also obscure the octopus's outline against the black-and-white sandy bottoms, or serve as an honest warning sign of the mimic's unpalatable flesh.

"While T. mimicus's imitation of flatfish is far from perfect, it may be 'good enough' to fool predators where it lives, in the world's center of marine biodiversity," Hamilton said. "These octopuses can change their color pattern to look similar to — but not exactly like — numerous toxic and non-toxic flatfishes in their area.”

First described by scientists in 1998, much remains unknown about the mimic octopus. Future research will focus on observing it in the wild in Indonesia, so that scientists can assess the possible reasons for its actions and better understand the costs and benefits of the strategy.

"This study reminds us that evolution does not have an endgame, but is a continuous process," Huffard added. "These octopuses will continue evolving as long as we can protect them and their habitat from threats like trawling, land reclamation and run-off."

The scientists detailed their findings in the September issue of the Biological Journal of the Linnean Society.

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Octopuses rely on visual cues to identify predators, prey and other marine creatures. Yet it has been difficult for researchers to study the animals' reactions to their natural environments, because the scientists can't control what might swim or crawl by an octopus — that is, until the advent of HDTV.

Researchers from the Sydney Institute of Marine Science found that by playing video on a liquid crystal high definition television for gloomy octopuses (Octopus tetricus), they could accurately see how the animals reacted to prey (a crab), a new object (a jar), and a potential predator (another octopus), responses usually only seen in the ocean. Observations reveal that that the individual octopuses have episodic personalities, according to details of the study published in The Journal of Experimental Biology.

"This new video playback technique is great news for researchers, because they can use it to study many different aspects of octopus behavior that can't otherwise be discerned using traditional techniques," lead author Renata Pronk, a marine biologist at Macquarie University in Australia, told LiveScience.

Video surveillance

Octopuses have very sophisticated eyesight, making everyday mirrors or videos, controllable tools that could help biologists see how the animals interact with their surroundings, ineffective in a lab. Essentially, the creatures know that the visuals aren't real.

New display technologies, however, make movies look more realistic, leading Pronk and her team to try HDTV. After some tinkering, they found that the octopuses reacted strongly to what they saw on the screen.

"This is the first time such a strong, appropriate response has been shown from a cephalopod to video," said Pronk. "The octopuses' reactions were the same as the way they react to these objects out in the ocean. For instance, when an octopus sees a crab out in the ocean, they generally try to sneak up or jet over to it and envelope it under their arms. This is how the octopuses reacted to the video crab."

The high-quality footage displayed with the latest and greatest technology led to the reactions, said Pronk. Seeing such significant responses, Pronk decided to explore whether the individuals had personalities by exposing them to videos over the course of a few days.

{{ video="LS_100319_Octopus0" title="Octopus Fooled by HDTV" caption="Octopus reacts to HDTV by attacking on-screen crab or hiding from the image of another octopus. Credit: Renata Pronk, Macquarie University & LiveScience.com" }} 

Personality episodes

If an octopus has a distinct personality, the researchers would expect to see the same behaviors from a certain individual consistently over time. Yet during the experiment, an octopus showed interest in the video one day, and seemingly became bored the next. Pronk uncovered that the octopuses have episodic personalities, meaning they display consistent traits over short periods of time, but longer-term, their behaviors changed completely.

"In short, they had what appear to be very short-lived personalities," she said.

Her discoveries, with the help of future experiments that use HDTV, could help marine biologists find out more about the behavior of octopuses and other cephalopods, like cuttlefish and squid.

"We can hopefully answer many more questions about cephalopod behavior using video playback," said Pronk. She would like to find out what it means when they change color, and if they can learn from each other. "This study raises even more questions about octopus personality," she said.

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Contrary to what was known, all octopuses are venomous, a new study finds.

Researchers knew that the blue-ringed octopus packed venom. Now they say all octopuses and cuttlefish, and some squid are venomous. In fact they all share a common, ancient venomous ancestor, the study indicates, and the work suggests new avenues for drug discovery.

While the blue-ringed octopus species remain the only group that are dangerous to humans, the other species have been quietly using their venom for predation, such as paralyzing a clam into opening its shell.

"Venoms are toxic proteins with specialized functions such as paralyzing the nervous system" said Bryan Fry of the University of Melbourne. "We hope that by understanding the structure and mode of action of venom proteins we can benefit drug design for a range of conditions such as pain management, allergies and cancer."

While many creatures have been examined as a basis for drug development, cephalopods (octopuses, cuttlefish and squid) remain an untapped resource and their venom may represent a unique class of compounds.

Fry obtained tissue samples from cephalopods ranging from Hong Kong, the Coral Sea, the Great Barrier Reef and Antarctica. The team — scientists from the University of Brussels and Museum Victoria — then analyzed the genes for venom production from the different species and found that a venomous ancestor produced one set of venom proteins, but over time additional proteins were added to the chemical arsenal.

The origin of these genes also sheds light on the fundamentals of evolution, presenting a prime example of convergent evolution where species independently develop similar traits.

The team will now work on understanding why very different types of venomous animals seem to consistently settle on the similar venom protein composition, and which physical or chemical properties make them predisposed to be useful as toxin.

"Not only will this allow us to understand how these animals have assembled their arsenals, but it will also allow us to better exploit them in the development of new drugs from venoms," Fry said. "It does not seem a coincidence that some of the same protein types have been recruited for use as toxins across the animal kingdom."

The study was published in the Journal of Molecular Evolution and announced today.

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It's hard enough to find fossils of hard things like dinosaur bones. Now scientists have found evidence of 95 million-year-old octopuses, among the rarest and unlikeliest of fossils, complete with ink and suckers.

The body of an octopus is composed almost entirely of muscle and skin. When an octopus dies, it quickly decays and liquefies into a slimy blob. After just a few days there will be nothing left at all. And that assumes that the fresh carcass is not consumed almost immediately by scavengers.

The result is that preservation of an octopus as a fossil is about as unlikely as finding a fossil sneeze, and none of the 200 to 300 species of octopus known today had ever been found in fossilized form, said Dirk Fuchs of the Freie University Berlin, lead author of the report.

Fuchs and his colleagues now have identified three new species of octopuses (Styletoctopus annae, Keuppia hyperbolaris and Keuppia levante) based on five specimens discovered in Cretaceous Period rocks in Lebanon. The specimens, described in the January 2009 issue of the journal Palaeontology, preserve the octopuses' eight arms with traces of muscles and rows of suckers. Even traces of the ink and internal gills are present in some specimens.

"The luck was that the corpse landed untouched on the sea floor," Fuchs told LiveScience. "The sea floor was free of oxygen and therefore free of scavengers. Both the anoxy [absence of oxygen] and a rapid sedimentation rate prevented decay."

Prior to this discovery only a single fossil species was known, and from fewer specimens than octopuses have legs, Fuchs said.

What most surprised Fuchs and his colleagues Giacomo Bracchi and Robert Weis was how similar the specimens are to modern octopus. "These things are 95 million years old, yet one of the fossils is almost indistinguishable from living species," Fuchs said.

This provides important evolutionary information, revealing much earlier origins of modern octopuses and their characteristic eight-legged body-plan, Fuchs said.

Unlike vertebrate animals, octopuses lack a well-developed skeleton, which allows them to squeeze into spaces that a more robust animal could not.

"The more primitive relatives of octopuses had fleshy fins along their bodies. The new fossils are so well preserved that they show, like living octopus, that they didn't have these structures," Fuchs said.

This insight pushes back the origins of the modern octopus by tens of millions of years, he said.

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Marine masters of disguise and octopus relatives, cuttlefish can instantaneously camouflage themselves against any background--even in the dark of night, proving that they must have extremely fine-tuned night vision, according to a new study.

Cuttlefish, octopuses and squid are members of a group of animals called cephalopods, which have evolved the ability to camouflage to hide from predators, such as fur seals, bottlenose dolphins, and barracudas, but the newly discovered abilities of cuttlefish have impressed scientists with their sophistication.

To blend in with their surroundings, stealthy cuttlefish use visual cues to match themselves to any background: sand, seagrass, rocks and coral. And they don't just match to color, but also the pattern, brightness and texture of their surroundings. For example, if they're settled against smooth algae, their skin will be smooth, but against rough, wrinkly algae, their skin will become wrinkled.

"Every time an octopus or cuttlefish moves one meter this way or that way, the visual background is usually different, and they adjust their pattern, so they have this on-going, wonderful system of fine-tuning their camouflage," lead study author Roger Hanlon of the Marine Biological Laboratory in Massachusetts said.

Keen eyesight

Most observations of these creatures have only been made during the day. Scientists weren't sure if cuttlefish all went into one camouflage pattern or if could make the same variations they did during the day.

Hanlon used a remotely operated vehicle (ROV) to spy on the cuttlefish at night. Because bright lights disturb the creatures, the ROV is equipped with a red light (cuttlefish can't see in that part of light spectrum) to help scientists see the cuttlefish's natural behavior.

Hanlon and his colleagues found that cuttlefish camouflaged themselves at night with the same degree of fine-tuning as during the day. He said this demonstrates their keen eyesight in the dark: "They can see sort of intensity and contrast and pattern really well at night, whereas we're terrible at night."

Predators' night vision

This fine-tuned response also means that predators must see in a variety of ways, forcing the cuttlefish to cover all the options.

"Visual predation at night must be very keen as well, otherwise [the cuttlefish] wouldn't bother making all this sophisticated match for every little nook and cranny they go to," Hanlon said.

Hanlon said it's likely that other cephalopods also camouflage themselves at night. The research appears in the April issue of The American Naturalist.

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You might never expect to tell a wobbly armed octopus to keep its elbows off the dinner table, but new research reveals the creatures stiffen their arms to form human-like joints to guide food to their mouths.

A three-jointed human arm has only seven degrees of freedom (DOFs), which are defined as the types of movements each joint can perform. Your shoulder and wrist each have three DOFs—each can tilt up and down, turn left and right, and can roll in a circular motion. Your elbow, however, only has one DOF, which is tilting up and down.

Scientists consider each of an octopus' eight arms to possess a virtually infinite number of degrees of freedom, allowing them to bend and twist freely. But when it's time to eat, octopuses use their flexible muscles to form temporary, quasi-articulated joints that work similarly to how human joints function.

Researchers recorded muscle activity in octopus limbs, and found that an arm generates two waves of muscle contractions that propagate toward each other. When the waves collide, they form a part-time joint.

This process occurs three times, forming a shoulder where the arm meets the body, a wrist where the suckers have grasped their food, and an "elbow" somewhere in between. The elbow typically exhibits the most movement during food retrieval.

The researchers say this is a remarkably simple and apparently optimal mechanism for adjusting the length of arm segments according to where the food item is grasped along the arm.

The similarity of structural features and control strategies between jointed vertebrate arms and flexible octopus limbs suggests that these configurations evolved separately in octopuses and vertebrates, a result scientists call an example of convergent evolution.

The research is detailed in the April 18 issue of the journal Current Biology.

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