Live Science's best of 2021: Writers' choice

This drawing shows how the dinosaur Psittacosaurus may have used its cloacal vent (aka butthole) for signalling during courtship.
This drawing shows how the dinosaur Psittacosaurus may have used its cloacal vent (aka butthole) for signalling during courtship. (Image credit: Bob Nicholls/ 2020)

What makes a science news story stand out? At Live Science, our reporters and editors cover a broad range of topics, and each year brings plenty of opportunities for each of us to share some of the strangest, most unexpected and most interesting science around.

Of the many hundreds of stories that we wrote about in 2021, some were truly unforgettable. From an immortal bee army to a dinosaur's perfectly preserved butthole, here are the stories that Live Science's writers just couldn't stop thinking about.

Pupil 'flex'

A close-up of an eye. (Image credit: Shutterstock)

Yasemin Saplokoglu, Staff Writer: Some people can wiggle their ears, some can lick their elbows… and it turns out, some people can grow and shrink their pupils on demand.

My favorite story to write this year was a case study on a 23-year-old student in Germany who can directly control his pupils like a muscle, something that was previously thought to be impossible. It was previously known that some people could change their pupil size when they wanted to but by using indirect methods, such as by thinking about the sun. But it was thought to be impossible that someone could control the pupils directly like a muscle, just by concentrating on the eye. The student, referred to in the study by his initials D.W., told the researchers he could feel gripping when his pupils were constricting, and relaxing when they were dilating. 

After publishing this article, I received so many emails from readers saying that they could do this too! I still get them sometimes. It's incredibly fun to find out that something which was thought to be impossible is actually much more common than we think.

Read more: Man can change his pupil size on command, once thought an impossible feat

Twisties and yips

Simone biles mid-twist during a vault at the Tokyo Olympics. (Image credit: Getty/ MARTIN BUREAU / Contributor)

Nicoletta Lanese, Staff Writer: My favorite story this year delved into the neuroscience of movement, which I'm a huge nerd about, and also featured one of my favorite Olympic events: gymnastics. Gymnast Simone Biles, the certified G.O.A.T., made headlines during this year's Olympics when she came down with a case of the "twisties," meaning she lost sense of where she was in the air during a trick. Other athletes have reported a similar disconnect between brain and body, called the "yips," where they suddenly can't execute the skills they honed in practice. I spoke with experts about the complex motor learning that goes into training these skills in the first place, and what likely goes wrong when an athlete gets the twisties or yips.

Read more: What's happening inside Simone Biles' brain when the 'twisties' set in?

Ancient beasts in a garden

Teeth from a mastodon skull unearthed in the foothills of the Sierra in California. (Image credit: , Chico (University Photographer Jason Halley/California State University)

Jeanna Bryner, Editor-in-Chief: When a person accidentally stumbles upon what ends up being a huge discovery, reporters like me take notice. And this year, the serendipitous find was giant in many ways: A park ranger who was ambling through a forest in California uncovered what ended up being a petrified forest chock-full of the fossilized remains of dozens of prehistoric behemoths, including a stunningly preserved mastodon skull, an extinct camel, rhinos, giant tortoises and even a monstrous 400-pound (181 kilograms) salmon ancestor. 

Greg Francek first noticed a wood-like structure poking from the ground; upon closer inspection, he realized the smooth protrusion was one end of a petrified tree. After finding a second, third, fourth and more of these tree remains, Francek realized he was in the middle of a petrified forest. I would’ve loved to have been there when he spotted the stunning window into the area’s past. His finding opened up a treasure trove for paleontologists and geologists. Over the past year, these scientists have unearthed hundreds of animal fossils representing dozens of species. These animals would have lived some 10 million years ago when the area was covered by an oak forest on the outskirts of the sea. 

Read more: Forest ranger stumbles onto garden of ancient beasts in California foothills

Poop-eating plateau pikas

A plateau pika (Ochotona curzoniae) outside of a nest hole, in Sichuan Province, Qinghai-Tibet Plateau, China. (Image credit: Nature Picture Library / Alamy)

Patrick Pester, Staff Writer: My favorite science story this year was about plateau pikas eating poop to survive Tibetan winters. The small, rabbit-like animals can't hibernate and don't migrate so scientists set out to understand how they cope with winters on high-altitude meadows in Asia, where temperatures fall to minus 22 degrees Fahrenheit (minus 30 degrees Celsius). The 2021 study found pikas slow their metabolism and, in some cases, eat domestic yak poop. Chowing down poop may help pikas spend less energy than they would foraging their own food and access water and nutrients that are scarce in winter.

What I loved most about the story is that biology professor John Speakman and his colleagues spent 13 years studying the creatures, while getting to know the local yak herders. Pikas were thought to directly compete with yaks for food, so this research can be seen as a feel-good story of an animal adopting a very unexpected survival strategy to make the most of human activity. 

Read more: Real-life Pikachus eat yak poop to survive Tibetan winters

So big, it shouldn't exist

A simulation of the giant arc structure located in the Bootes Constellation (Image credit: Alexia Lopez/UCLan)

Tia Ghose, Assistant Managing Editor: My favorite story of the year was about a 3.3 billion-light-year arc across the cosmos that is so big, it shouldn't exist. The structure, aptly named the Giant Arc, spans a 15th of the observable universe, and yet we only discovered it this year. The cosmic behemoth's sheer size challenges the cosmological principle, a long-held assumption stating that at large scales, matter is uniformly distributed. (According to this principle, there are limits to how big a structure can get.) 

Astronomers spotted this gargantuan structure serendipitously, while they were constructing a cosmic map using light from quasars, or ultrabright galactic cores that beam radio waves. I love this story because it highlights the vastness of the universe and shows that even some truly big discoveries are hiding in plain sight. It reminds me there are likely infinitely more strange and mysterious objects lurking in the universe just waiting to be found.

Read more: 'Giant arc' stretching 3.3 billion light-years across the cosmos shouldn't exist

Caterpillar-drinking butterflies

Parantica cleona, an Indonesian butterfly, contemplates its next meal. (Image credit: Yi-Kai Tea)

Mindy Weisberger, Senior Writer: One of the things that I love the most about covering animal science is that the natural world is a neverending source of beauty and wonder — but it's also a place steeped in unmitigated horror. And nowhere was that more true in 2021 than in the discovery that butterflies slash open the bodies of caterpillars to slurp out their insides. 

Researchers in Indonesia watched seven species of milkweed butterflies as they sipped on "wounded and oozing caterpillars." Sometimes these grisly meals lasted for hours.

The butterflies used tiny claws on their feet (yes, butterflies have claws) to scratch wounds in caterpillars' bodies, and then lapped up the liquid that oozed out. What fascinated me about this was why the butterflies were doing it: because caterpillars are basically stuffed full of full of chewed-up milkweed residue, and butterflies are attracted to certain compounds in milkweed as protection against predators and for producing pheromones that attract females. Caterpillars are brimming with milkweed goodness, and that makes them an irresistible (if somewhat gruesome) snack.

Read more: Milkweed butterflies tear open caterpillars and drink them alive

Mysterious Mexican mangroves

Scientists have uncovered the secret origins of a mysterious landlocked mangrove forest in Mexico. (Image credit: Shutterstock)

Harry Baker, Staff Writer: My favorite story this year was about a mysterious mangrove forest in the heart of Mexico's Yucatan Peninsula. 

Normally, mangroves only grow in saltwater conditions along tropical coastlines or in estuaries. But these particular mangroves live in freshwater more than 125 miles (200 kilometers) from the nearest ocean. This ecological enigma had baffled scientists for years, until a new study this year finally uncovered the mangroves' mysterious origins.

It turns out that the forest took root in the area around 125,000 years ago when sea levels were much higher than they are today. After the sea level dropped, the mangroves were able to adapt to living in a freshwater system and evolved into a one-of-a-kind ecosystem. 

I enjoyed this story because it shows the power of evolution on a much larger and faster scale than we normally see.

Read more: Mysterious Mexican mangrove forest is 'trapped in time' hundreds of miles from the coast

The 'perfect' and 'unique,' dinosaur butthole

This drawing shows how the dinosaur Psittacosaurus may have used its cloacal vent (aka butthole) for signaling during courtship. (Image credit: Bob Nicholls/ 2020)

Laura Geggel, Editor: I've covered a lot of dinosaur news — the discovery of new species and investigations into how dinosaurs grew and behaved — but never have I written about a fossilized butthole. Scientifically, it's known as a cloacal vent — a multipurpose "backdoor" opening used for pooping, peeing, breeding and egg laying. This is the first preserved dinosaur nether region on record, and the researchers apparently struck gold because it's not like any other known to science. "It's its own cloaca, shaped in its perfect, unique way," study lead researcher Jakob Vinther, a paleobiologist at the University of Bristol in the United Kingdom, told Live Science. 

It helps that this well-preserved booty belongs to a cutie: Psittacosaurus, a bristly tailed, Labrador-size, horn-faced dinosaur that lived during the Cretaceous period (145 million to 66 million years ago). Psittacosaurus may be long gone, but you've got to appreciate how its derrière is shedding light where the sun don't shine.

Read more: 1st preserved dinosaur butthole is 'perfect' and 'unique,' paleontologist says

The ultra-rare planet in Orion's nose

GW Orionis has three stars centered within three wobbly rings of dust. Astronomers think there could be a rare, three-sun planet in the mix too. (Image credit: ESO/L. Calçada, Exeter/Kraus et al.)

Brandon Specktor, Senior Writer: The idea of anything hanging out "in Orion's nose" is inherently funny to me. All the better if that thing happens to be the rarest type of planet in the entire universe: A single world orbiting three suns simultaneously.

That's why my favorite story this year was about the star system GW Orionis (or GW Ori) – located 1,300 light-years from Earth at the tip of the Orion constellation's nose. The star system looks like a giant orange bullseye made of three wobbly, concentric rings of space dust. At the center of those rings are two stars tightly orbiting one another; a little further out, a third star orbits that binary pair. Triple-star solar systems aren't unheard of, but GW Ori is special because scientists are pretty certain that there is an enormous, Jupiter-sized planet lurking in one of the system's dusty rings – the only triple-sun (or "circumtriple") planet in the known universe. 

That's incredible – and so are the researchers' images and illustrations of the ultra-rare system. Eat your heart out, Tatooine! 

Read more: Exceptionally rare planet with three suns may lurk in Orion's nose

Bee creates immortal 'clone army'

The Cape honeybee worker has been shown to clone itself millions of times. (Image credit: Shutterstock)

Ben Turner, Staff Writer: Looking back into the history of the natural world, it’s always tempting to view the process of evolution through the lens of the apparent perfection it creates. Take the biomechanical clockwork of the human eye; or the sculpting of a hummingbird’s beak to drink the nectar from the thinnest flower; or the apparent artist’s mania that not only finesses a butterfly mimic’s wings to appear as a leaf, but even adds markings to resemble caterpillar-chomped holes.

My favorite story this year is about how in the short-term, evolution is random, messy and even a little ugly. It’s about how a genetic fluke in a South African bee species enabled its workers to create perfect copies of itself, and how the species was subsequently transformed into an immortal army of parasitic clones.

The bees ended up developing all kinds of weird and sneaky strategies, from hatching plots to insert their clones into positions of power to completely taking over other hives with their entitled, layabout offspring. It plays out like an all-bee version of "Game of Thrones," and, given the insects’ complete lack of genetic diversity and consequent susceptibility to disease, the finale is likely to be just as disastrous. 

Ecologically terrible though it may be, this story digs into fascinating questions about the balance between sociality and selfishness, and how evolution’s perfection is only visible in the long-run.

Read more: Single bee is making an immortal clone army thanks to a genetic fluke

Originally published on Live Science.

Mindy Weisberger
Live Science Contributor

Mindy Weisberger is an editor at Scholastic and a former Live Science channel editor and senior writer. She has reported on general science, covering climate change, paleontology, biology, and space. Mindy studied film at Columbia University; prior to Live Science she produced, wrote and directed media for the American Museum of Natural History in New York City. Her videos about dinosaurs, astrophysics, biodiversity and evolution appear in museums and science centers worldwide, earning awards such as the CINE Golden Eagle and the Communicator Award of Excellence. Her writing has also appeared in Scientific American, The Washington Post and How It Works Magazine.