11 Facts About the Animals of Chernobyl

Claudia Dimuro
Jon Mayer
A fox in the Chernobyl Exclusion Zone.
A fox in the Chernobyl Exclusion Zone. / Antoine Rouleau/Moment/Getty Images

Almost four decades after the Chernobyl disaster—the world’s worst nuclear accident—signs of life are returning to the exclusion zone. Wild animals in Chernobyl are flourishing within the contaminated region; puppies roaming the area are capturing the hearts of thousands. Tourists who have watched the critically acclaimed HBO series Chernobyl are taking selfies with the ruins. Once thought to be forever uninhabitable, the Chernobyl Exclusion Zone has become a haven for flora and fauna that prove that life, as they say in Jurassic Park, finds a way.

1. The animals of Chernobyl survived against all odds.

A faulty design and improperly trained workers are two of the precipitating factors that led to an explosion in Reactor 4 of the Chernobyl nuclear power plant on April 26, 1986. The disaster devastated the environment: The total amount of radioactive material eventually released was hundreds of times higher than seen in the atomic bombing of Hiroshima.

Around the plant and in the nearby city of Pripyat in Ukraine, the Chernobyl disaster’s radiation caused the leaves of thousands of trees to turn a rust color, giving a new name to the surrounding woods: the Red Forest. Workers eventually bulldozed and buried the radioactive trees. Squads of Soviet conscripts also were ordered to shoot any stray animals within the 1000-square-mile Chernobyl Exclusion Zone. Though experts today believe parts of the zone will remain unsafe for humans for another 20,000 years, numerous animal and plant species not only survived, but thrived.

2. The absence of humans is returning Chernobyl to wilderness.

As WIRED points out, the Chernobyl disaster presents an unintended experiment in what Earth would be like without humans. Hunting is strictly illegal and living within the Chernobyl Exclusion Zone is not recommended. The fewer humans there are, the more nature can re-establish itself unencumbered by human activity. According to The Guardian, an official nature reserve recently created on the Belorussian side of the zone claims to be “Europe’s largest experiment in rewilding,” where animals are losing their fear of humans. In fact, a few species are actually living better within the Chernobyl Exclusion Zone than outside of it.

3. Bears and wolves outnumber humans around the Chernobyl disaster site.

A beaver swims in a former cooling water pond inside the exclusion zone.
A beaver swims in a former cooling water pond inside the exclusion zone. / Sean Gallup/GettyImages

According to biologist Jim Beasley, the population of large mammals in the exclusion zone has surpassed the numbers found before the near-meltdown. Bears, wolves, lynx, bison, deer, moose, beavers, foxes, badgers, wild boar, and raccoon dogs are just some of the species that have seemed to find a happy home in the radioactive area. Along with the larger animals, a variety of amphibians, fish, worms, and bacteria make the unpopulated environment their home.

A constant dose of low-level radiation obviously isn’t beneficial, but it may be the case—for some animals, at least—that it isn’t deleterious enough to outweigh the pre-disaster impact of human beings encroaching on habitats and actively hunting wildlife.

Wolves, in particular, may benefit from their propensity to travel great distances, giving them the opportunity to dilute the amount of radiation consumed during hunting. Beasley pegged the population density of the Chernobyl wolves as significantly higher than that found in America’s Yellowstone National Park. The biologist told National Geographic that “humans have been removed from the system and this greatly overshadows any of those potential radiation effects.”

4. An endangered wild horse is making a comeback thanks to Chernobyl.

Przewalski horse rolls on its back in a field
A Przewalski horse in Eastern Germany. / PATRICK PLEUL, AFP/Getty Images

The Smithsonian’s National Zoo & Conservation Biology Institute called Przewalski’s horses “the last truly wild horse.” Other species sometimes referred to as wild, like the kind you might find on the United States’ Assateague Island National Seashore, are properly classified as feral domestic horses—they descend from horses that escaped domestication. Whether Przewalski horses—also called Takhi—can truly be called a wild species or subspecies is actually a matter of some debate. But what’s clear is that a once-large population that ranged across large swaths of Asia and Europe was eventually reduced to almost nothing. When Lee Boyd and Katherine A. Houpt edited a book about the animal in 1994, the most recent wild sighting had occurred in the late ‘60s, leading the authors to declare them “extinct in the wild.”

But British ecologists Mike Wood and Nick Beresford, who specialize in studying the effects of radiation on Chernobyl’s wildlife, observed that the Przewalski’s horse is thriving within the CEZ. In the late 1990s, about 30 Przewalski’s horses were released in the Ukrainian side of the CEZ, and that population has increased to more than 200. Based on camera trap images, Wood estimated that some of the original horses (identified by their brand markings) are still alive. Photos of juvenile horses and foals also indicated that the population is expanding.

5. Radiation may have killed off Chernobyl’s insects.

In contrast to large carnivores and other big fauna, insects and spiders have seen a big drop in their numbers. A 2009 study in Biology Letters indicated that the more radiation there was in certain locations around the Chernobyl disaster area, the lower the population of invertebrates. A similar phenomenon occurred after the 2011 nuclear accident at the Fukushima nuclear power plant. Bird, cicada, and butterfly populations decreased, while other animal populations were not affected.

6. Chernobyl animals are mutants ...

Scientists have noted significant genetic changes in organisms affected by the disaster: According to a 2011 study in Biological Conservation, Chernobyl-caused genetic mutations in plants and animals increased by a factor of 20. Among breeding birds in the region, rare species suffered disproportional effects from the explosion’s radiation compared to common species. Further research is needed to understand how the increased mutations affect species’ reproductive rates, population size, genetic diversity, and other survival factors.

In 2018, scientist Michael Byrne tracked a wolf traveling a great distance—ultimately outside of the Exclusion Zone—and wondered whether the disproportionately high number of mutations in the Chernobyl animals could be passed on to other populations. Byrne struck an even-handed chord regarding his speculation: “I don’t want to say that animals from Chernobyl are contaminating the world. But if there are any forms of mutations that could be passed on, it’s a thing to consider.”

7. ... but that might not show up how you expect.

A giant catfish in a contaminated cooling pond at the Chernobyl nuclear power plant in 2017.
A giant catfish in a contaminated cooling pond at the Chernobyl nuclear power plant in 2017. / Sean Gallup/GettyImages

That doesn’t mean there’s a bunch of three-eyed fish or two-headed cows in the Exclusion Zone, though. In 2016, footage of some very large catfish in the cooling pond of the Chernobyl reactor spread online, leading some to conclude that the radiation had supercharged the fishes’ growth. It’s doubtful that the mutations caused by radiation, though, would lead to a larger overall size. These types of mutations generally decrease an animal’s fitness and ability to grow to full size, let alone some kind of Hulk-like supersize. The explanation for the large catfish was actually quite simple: some fish are just really big. 

There have been some oddities recorded within the area, and tour guides tell visitors not to pet Chernobyl animals due to potential radioactive particles in their fur, but today’s wild animals are sporting their normal number of limbs and aren’t glowing. It seems that the most dramatic genetic mutations occurred immediately after the explosion at Reactor Four, consistent with what we’ve observed in human beings. About 30 people died within months of the original explosion, primarily from acute radiation syndrome. Longer-term deaths related to the disaster are a matter of considerable debate, though there is evidence that thyroid cancer rates were elevated in people (especially children) exposed to Chernobyl’s radiation—possibly through contaminated food. Perhaps surprisingly, a study published in the journal Science showed that parents who experienced genetic mutations as a result of radiation exposure did not pass those mutations on to their children

It makes some sense that the biggest impacts would be felt in the immediate aftermath of the disaster, given how radiation works. Over the years, some of the potentially harmful radionuclides released by the blast have decayed, presumably making the area less dangerous to live in. Uncontrolled iodine-131 exposure, for example, is known to increase the risk of thyroid disease, including cancer. But it has a halflife of only eight days, and would have basically disappeared from the zone within a few months. 

8. Voles demonstrate a number of concerning trends …

Other radioactive isotopes are still present in significant quantities. Cesium-137, for example, has a half life of over 30 years. And some animals are disproportionately affected: One risk factor is the animal’s diet. Voles, for example, are a type of adorable little rodent that likes to eat a lot of mushrooms. Unfortunately, some mushroom species happen to be particularly good at concentrating radiation, passing on the harmful material to hungry voles. And they seem to demonstrate the harmful effects of radiation in a number of ways: The critters were shown to be less fertile in areas with higher concentrations of radiation, with a corresponding drop in overall populations. They were also shown to have higher rates of cataracts than animals from outside the Exclusion Zone.

9. ... As do birds.

Barn swallows in the area were shown to demonstrate elevated levels of partial albinism, presumably a result of radiation-related genetic mutations. Areas with higher levels of radiation also seemingly gave rise to bird populations with smaller brains, less viable sperm, and decreased species diversity and abundance. So the story of Chernobyl’s animals isn’t a simple one of the land returning to some kind of fecund paradise, but it also isn’t the barren wasteland you might have imagined.

10. Some Chernobyl dogs were adopted.

The Stray Dogs Of Chernobyl
A stray dog outside the giant enclosure that covers devastated Reactor Number Four at the Chernobyl nuclear power plant in 2017. / Sean Gallup/GettyImages

Hundreds of pooches—the descendants of dogs abandoned by their owners during the site’s evacuation on April 27, 1986—have made the desolate area their home. Now, an organization called the Clean Future Fund helps conduct sterilization campaigns in the area. They also provide medical care, vaccinations, and even food to the Chernobyl pups (and cats). 

Back in 2018 and 2019, a number of dogs were identified as having safe levels of radiation, and a few dozen were actually adopted. As of mid-2022, it seemed that the combination of the pandemic and the Russian invasion of Ukraine have disrupted the organization’s efforts, though they do continue to do occasional work in the Exclusion Zone.

11. There are humans in the Exclusion Zone as well.

A woman in the Chernobyl Exclusion Zone talking to her dog
Zinayida Trofimivna Huzienko, 93, talks to her dog inside of her home in the village of Ilintsi near Chernobyl, Ukraine, in 2006. / Daniel Berehulak/GettyImages

Some of the Chernobyl dogs have been adopted by people who live in the Exclusion Zone. Despite laws ostensibly prohibiting it, there are actually a number of human beings living in the Exclusion Zone, some with tacit permission from authorities. These residents are called Samosely, or self settlers. They’re mostly seniors, mostly women, and mostly lived in the area before the nuclear disaster. For any number of reasons, the Samosely have decided that the potential risks of radiation are outweighed by other considerations—financial, cultural, and geopolitical—that called them to the area.

This story is an adaptation of a previously published post (which ran in 2019) and an episode of The List Show on YouTube and has been updated for 2023.