The 12 most intriguing animal discoveries of 2021

Here are our editors’ picks for the most compelling wildlife findings of the year, from ants that can regrow their brains to the world’s tiniest reptile.

Published 9 Dec 2021, 09:52 GMT
tuskless-elephant
Tuskless female elephants are proliferating in Gorongosa National Park, Mozambique. The country’s civil war led to widespread poaching, which killed most elephants and led some survivors to evolve a lack of tusks.
Photograph by Elephant Voices

As we approach the third year of the COVID-19 pandemic, amid increasingly destructive climate change, news coverage of science can sometimes be a heavy read.

But Earth is still an incredible place, bursting with promise and mystery. Research into the wonders of the natural world continue to show us how amazing life on our planet really is.

Here are the top 12 animal discoveries that got our attention this year.

‘Virgin births’ in a rare bird 

California condors—magnificent scavengers with a wingspan of over nine feet—almost went extinct by the middle of the 20th century, due to poisoning, poaching, and habitat destruction. In an ambitious bid to save them, all 22 condors were captured from the wild in 1987 and bred in captivity, before being released back to parts of California, Utah, Arizona, and Baja California. The total population is now more than 500.

Researchers have kept careful track of the birds’ breeding habits and genetics, and in October, they discovered that two female birds had given birth to young—without breeding. This is the first evidence of virgin birth, also known as parthenogenesis, in this species (and likely any non-domesticated bird). Scientists think that this form of reproduction is significantly more common in the animal world than thought, in part because it’s difficult to detect and rarely tracked.

Although parthenogenesis could serve as a life raft for rare species when mates are scarce, it could also have downsides, such as reducing genetic diversity.

Why did this happen? “We just don’t know,” says Oliver Ryder, director of conservation genetics at the San Diego Zoo Wildlife Alliance. “Will it happen again? I rather believe so.”

COVID-19 found in wild deer, other animals 

The virus that causes COVID-19 doesn’t just afflict humans: It can also infect a wide variety of animal species.

So far, researchers have found evidence of infection in captive or domesticated animals, including tigers, lions, gorillas, minks, snow leopards, domestic dogs, and domestic cats. Generally, the virus is thought to cause mild symptoms in other animals.

But the virus also infects wild white-tailed deer in North America. Scientists in Iowa found active infections in about 80 percent of deer, according to research published in November on bioRxiv, a site that posts preliminary scientific findings. The analysis suggests that deer have been infected multiple times from people and are passing it to one another‚ though nobody knows how deer might have picked up the virus. This research is similar to a U.S. study published earlier in the year showing that 40 percent of 152 deer tested in three states—Michigan, Illinois, and New York—had antibodies to SARS-CoV-2.

Having a reservoir of the virus in a common animal is concerning, since deer could potentially transmit it back to humans, researchers say.

World’s smallest reptile discovered 

In February, researchers announced a new species of chameleon discovered in a rainforest in northern Madagascar, named Brookesia nana, or B. nana for short. This so-called nano-chameleon is about the size of a sunflower seed, and may be the smallest reptile on Earth.

Finding such a tiny reptile raises interesting questions about the lower limits of body size in vertebrates. It also highlights the astonishing—and highly threatened—biodiversity of Madagascar, scientists say. Its discoverers suspect the chameleon will soon be listed as critically endangered.

The newfound species, Brookesia nana, found in northern Madagascar, is likely the smallest reptile on Earth.
Photograph by Frank Glaw, Zoologische Staatssammlung München

Black-footed ferret cloned 

To save another endangered species, scientists have successfully cloned a black-footed ferret, using preserved cells from a long-dead wild animal. It's the first time any native endangered species has been cloned in the United States.

The achievement, announced in February, is a major advance, since there are only about 500 black-footed ferrets remaining—all of which are closely related and descendants of a single colony found in 1981 in Wyoming after the species was thought to be extinct.

But cells from one female named Willa, who died in the mid-1980s without reproducing, were preserved on ice at the Frozen Zoo, a program of San Diego Zoo Wildlife Alliance. These cells have now been cloned and made into a viable ferret named Elizabeth Anne.

Researchers hope that her offspring will be able to be reintroduced to the wild in the coming years, injecting a much needed dose of genetic diversity into the inbred population.

World’s bee diversity hotspot found 

The San Bernardino Valley, straddling Arizona and Mexico, is one of the most important inland wetlands in the U.S. Southwest. Over the eons, water has travelled south from the mountains and forced its way out of artesian wells, giving rise to a bevy of plants and flowers throughout the year. This diversity of plants also supports a huge range of insects, including bees.

In April, a study published in the Journal of Hymenoptera Research, found that 497 species of bees live within just over six square miles of the valley. This is, by far, the highest concentration of bee diversity on Earth.

The discovery makes crucial the need to protect the valley, which has suffered from the construction of the border wall, a 30-foot steel fence that bisects the valley. Builders used vast amounts of aquifer water to make cement for the base of the wall, which caused springs in the valley to dry up.

A group of solitary bees known as Svastra duplocincta. Males of this species gather together at night to roost and sleep upon plants, grasping them with their mandibles so they don’t fall off.
Photograph by Bruce D Taubert

Some elephants are evolving to lose their tusks

Mozambique’s civil war, which lasted from 1977 to 1992, was brutal for African elephants: More than 90 percent of the animals were killed for ivory in the country’s Gorongosa National Park. But the carnage had an unexpected result: Some elephants are evolving without tusks—thus giving them a lower chance of being killed by poachers.

As National Geographic previously reported, about a third of younger female elephants in Gorongosa, born after the war ended in 1992, never developed tusks.

Research published in October in Science shows that such elephants have mutated copies of two genes that normally promote tusk development.

Normally, tusklessness would occur only in about 2 to 4 percent of female African elephants.

Jaguars moving into the U.S., reclaiming old territory 

Arizona and New Mexico are traditional jaguar territories: As recently at the early 1900s the big cats were found throughout both states, and as far north as the Grand Canyon. But in the past 15 years, a total of seven male jaguars have been reported in Arizona.

As National Geographic reported in March, scientists now know that one adolescent male jaguar inhabits protected land a few miles south of the border where Mexico, Arizona, and New Mexico meet—a sign that the species may be extending north from a breeding population in Sonora, Mexico.

It’s possible the feline could eventually reclaim parts of their former U.S. range, scientists predict, if the animals themselves and their wildlife corridors are protected—and if the border wall does not further expand.

Wild horses and donkeys dig desert wells 

Though some consider wild horses and donkeys, or burros, to be an introduced menace, they can impact their environment in ways that help other animals.

In April in the journal Science, scientists reported these animals can use their hooves to dig more than six feet deep to reach groundwater, in turn creating oases that serve as a boon to other wildlife. The team found such wells in the Sonoran Desert, in western Arizona, and in the Mojave Desert, recording a total of 57 species that visited the water sources. These include American badgers; black bears; and an array of birds, including some declining species, such as elf owls.

The behaviour fits the definition of “ecosystem engineering,” a phenomenon whereby wildlife alter their environment, says study author Erick Lundgren, a postdoctoral researcher at Aarhus University in Denmark.

These sea slugs chop off their own heads 

Usually, when an animal loses its head, that animal’s life is over. But not so for some sea slugs. As described in a study published in March in Current Biology, two species of the marine animals can rip off their own heads. Each dismembered head can then regenerate an entirely new body.

These creatures are also unusual in that they can steal chloroplasts from algae and potentially harvest energy from the sun within their own bodies.

Researchers are interested in such extreme examples of bodily regeneration, which could have implications for human medicine. (Learn more: Solar-powered sea slugs hide wild secrets.)

Scientists say more research is needed to explain the recent discovery that two species of sea slugs can rip off their heads and regenerate new bodies.
Photograph by Sayaka Mitoh

Cockatoos learn from their kin 

Do animals have culture? If culture consists of a shared set of behaviours that can be passed between individuals, then the answer is yes. But studies of animal learning and culture often focus on a specific group of mammals, such as cetaceans and great apes. Scientists wanted to know if parrots also have culture.

In the suburbs of Sydney, Australia, some sulphur-crested cockatoos—a gregarious, colourful parrot—have figured out how to open bin lids, allowing them access to a new food source, according to a July study in the journal Science. Other cockatoos quickly copied the behaviour.

This discovery means that parrots “have joined the club of animals that show culture,” says study leader Barbara Klump, a behavioural ecologist at the Max Planck Institute of Animal Behaviour in Germany.

Whale migration sets records 

How far can a whale swim?

A grey whale set the world record for a marine vertebrate, traveling more than 16,700 miles—over halfway around the world, according to a study published in June in the journal Biology Letters. The male cetacean, spotted off Namibia in 2013, is also the first grey whale ever observed in the Southern Hemisphere.

When study co-author Simon Elwen, a zoologist at the University of Stellenbosch, South Africa, first heard of the 2013 sighting, he was skeptical.

“It’s like someone saying they saw a polar bear in Paris—technically it could get there, but it just doesn’t seem very realistic.” But research showed that the whale’s genes matched those from the known population in the North Pacific.

Ants can shrink and regrow their brains

Indian jumping ants, a species with forceps-like jaws and large black eyes that inhabit forests along India’s western coast, have a strange way of picking queens. To do so, workers host competitions in which the winner becomes the monarch, capable of producing eggs. The winning female’s ovaries expand, and her brain shrinks up to 25 percent.

But these queens can also be taken off their pedestal and become workers again, causing their reproductive organs to shrink and the brain to expand once more—an extraordinary feat not previously known to occur in insects, according to a study published in April in the Proceedings of the Royal Society B: Biological Sciences.

“In the animal world,” explains study leader Clint Penick, of Kennnisaw State University in Georgia, “this level of plasticity—and especially reversible plasticity—is pretty unique.”

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