1. The disaster

One of the worst accidents in history began as a safety test. Engineers wanted to study the efficacy of a new procedure to cool the reactors—but in order to perform the experiment, they had to shut down the power to simulate an outage.

A house in an abandoned village in Khoiniki District in Belarus' Gomel Region. Gomel Region. Some of its territory remains part of the Chernobyl exclusion zone.
(Photo by Viktor Drachev/TASS via Getty Images)

In retrospect, it’s easy to recognize the stupidity of the error. Soviet chemist Valery Legasov said in 1987: “It was like airplane pilots experimenting with the engines in flight.”

An unexpected power surge caused an explosion, killing two people instantly and spreading radiation throughout the Ukrainian village. It’s hard to know the full death toll because of the long-term, generational effects of the nuclear disaster. Estimates range between 4,000 and 93,000 deaths.

To this day, the ghost town is largely uninhabitable…for humans.

2. Evacuation of Chernobyl

Some of the most heartbreaking stories about the Chernobyl disaster involve families who had to leave their village homes. Told they would be able to return shortly, the exclusion zone is still too irradiated to allow humans to live there.

A female moose stands in the middle of a snow covered road and observes from a distance near the village of Berestochok on February 1, 2006 near Chernobyl, Ukraine.
(Photo by Daniel Berehulak/Getty Images)

However, the absence of around 350,000 humans appears to have benefited the local species of wild animals. Bison, bears, foxes, deer, and elk are only some of the species of wild animals that have flourished from the evacuation of all humans. Though few animals close to the blast would have survived the explosion and heavy levels of radiation, the surviving animals seem to have adapted quite well.

3. The absence of humans has allowed mammals to thrive

Chernobyl’s several exclusion zones combine to stretch 1,600 square miles—making it one of the largest wild animal sanctuaries in Europe.

Motion-sensing camera traps in the exclusion zone have captured many mammals who appear to be enjoying the absence of humans. Human activities like overhunting and wiping out animal habitats are known to cripple animal populations, so it stands to reason that the lack of humans in the area also limits danger to animals.

Red fox thrives in the exclusion zone, Chernobyl
(Vic Harkness/Wikimedia)

The wolf population in Chernobyl is said to be thriving so much that scientists were able to locate a wolf pack simply by howling and listening for the wolves to respond.

It’s also easy to observe signs of nature’s engineer—the booming Ukrainian beaver population has left its fingerprints everywhere, knocking down trees, building dams, and drastically changing the landscape of the region.

4. Semiaquatic wildlife also seems to be on the rise

A recent 2019 study using camera traps showed that semiaquatic animals, like minks and otters, are able to survive in the exclusion zone. Scientists placed fish carcasses near the edge of rivers and aimed cameras at them to see who would come up to feast on them.

River otters have returned to the exclusion zone, Chernobyl.
(Photo by Arterra/Universal Images Group via Getty Images)

98 percent of the fish carcasses were consumed by wildlife within one week. Scientists were able to snap pictures of river otters, minks, and even white-tailed eagles. It’s the first time scientists have observed some of these creatures in the area since the disaster. The fact that the fish carcasses were consumed so quickly shows that there is a high rate of scavenging occurring in the area—good news for animal researchers.

5. Giant catfish are common in Chernobyl’s radioactive cooling pond

Despite what you may have learned from the “Godzilla” franchise, radiation does not cause gigantism. In fact, very few mutations will lead to an increase in size, and radiation poisoning is much more likely to lead to a reduced size in species. This is because growing big takes energy, and a sick animal must expend its energy on survival and fighting off disease.

A giant catfish swallows a piece of bread while swimming in a contaminated cooling pond at the Chernobyl nuclear power plant.
(Photo by Sean Gallup/Getty Images)

The real reason for the giant catfish in Chernobyl is much less exciting. Catfish have voracious appetites—and they will eat nearly anything. Combine their insatiable eating habits with the lack of predators or stiff competition, and you can easily see how they can grow quite large in the cooling pond.

That being said, you’re much more likely to find genetically deformed catfish in the pond, so that’s still a bit disturbing.

6. The red fox is a common sight in the exclusion zone

The red fox is one of the most resourceful creatures in the world. It should be no surprise, then, that the animal has done well for itself—even in areas with especially high radioactivity. The mischievous mammal is often sighted by visitors and on camera traps all around Chernobyl.

A visitor feeds a docile fox in the ghost town of Pripyat not far from the Chernobyl nuclear power plant.
(Photo by Sean Gallup/Getty Images)

Because the foxes are not used to the sight of humans, it’s been theorized that they are less afraid of us than outside foxes—they often approach visitors in the hopes of receiving a tasty snack. The red fox has the widest geographic range of any carnivora—further proof that animals are choosing to brave the contaminated area.

7. Przewalski’s horses were introduced to the area

This endangered species of wild horse was brought to the area in the 1990s as part of a conservation experiment. Przewalski’s horses are considered to be the only “true” breed of wild horse, since other species evolved from feral domestic horse breeds.

A photo taken on January 22, 2016 shows wild Przewalski's horses on a snow covered field in the Chernobyl exclusions zone.
(Photo credit: GENYA SAVILOV/AFP/Getty Images)

The experiment has been successful: the horses are thriving due to the lack of human interference—scientists believe the population of the endangered species continues to increase. The horses that were brought in from zoos and other locations mostly died off, while the ones that previously roamed the nearby area before being introduced to the exclusion zone adapted well to the environment; they bred and formed the foundation for future generations.

8. Bison are thriving in the exclusion zone

The European bison population in Chernobyl is said to have grown ten times since 1996. The lack of hunting in the area probably deserves credit for the booming increase. Camera traps frequently capture footage of the imposing creatures as they graze on the forest grass. The large beasts are surprisingly limber—they are able to jump two meters in the air without a running start.

Bison in the 30-km exclusion zone around the Chernobyl nuclear reactor.
(Photo credit: VIKTOR DRACHEV/AFP/Getty Images)

The long-term effects of radiation on bison are still unknown. They have a fairly short average life span of 24 years in the wild, and scientists have found dead bison in the area with both high and negative levels of radiation.

9. Brown bears have returned to Chernobyl

Brown bears hadn’t been observed in the area for a century, but they’ve since returned. There had been signs that the bears had returned, but scientists were able to provide photographic evidence of their return in 2014. It seems that without humans hunting them and disturbing their habitat, the bears have found a new home in the exclusion zone.

Bears painted by a graffiti artist adorn the facade of an abandoned cultural center in the ghost town of Pripyat not far from the Chernobyl nuclear power plant.
(Photo by Sean Gallup/Getty Images)

With the thriving wildlife populations around them, there is a lot more food for the bears to consume. It remains unknown how radiation poisoning affects the bears—scientists have begun fitting collars on many large animals to measure the radiation levels and track their migration habits to see how freely they move through the highly contaminated areas.

10. Eurasian lynx have returned after vanishing for half a century

Like the brown bear, many assumed the Eurasian lynx had fled the area for good. Recent years have given hope to researchers, as they began to notice tracks and scratches on tree branches consistent with the felines—but concrete proof came once again thanks to a motion-sensing camera trap.

The Eurasian Lynx has returned to Chernobyl.
(Photo by Arterra/Universal Images Group via Getty Images)

The camera captured footage of three separate lynx families perusing the exclusion zone in Chernobyl, probably hunting for deer or smaller prey like foxes or rabbits. The felines are strict carnivores, which means they too have been drawn back into the area by the influx of new tasty prey, braving the highly contaminated terrain.

11. Wolves in Chernobyl are doing especially well

While it remains a debate between scientists as to how well wildlife is thriving in the exclusion zone compared to outside areas, at least one animal population appears to be doing especially well in the contaminated area. The wolf population in the exclusion zone is seven times that of outside areas.

Wolf populations increasing in the exclusion zone.
(Photo credit: Costfoto/Barcroft Media/Barcroft Media via Getty Images)

Drawn there by the abundance of prey, habitat unmolested by humans, and limited competition with other predators, many wolves have made the contaminated area their new home. The success of the wolves, while heartening, is also concerning for some researchers, who are alarmed by what it could mean for the future of wolves in the area.

12. Wolves in Chernobyl may be spreading mutations

The wolves from the exclusion zone have been doing so well—and moving so freely—that some researchers have major concerns about them spreading physiological mutations by breeding with wolves outside of the affected area. Scientists are monitoring the distance that the wolves travel by fitting them with tracking collars.

Wolf population growing in Chernobyl.
(Photo by Monika Skolimowska/Picture alliance via Getty Images)

Researchers were able to track one wolf that made the trek from the exclusion zone in Ukraine all the way to Belarus, and on to Russia—a combined distance of 250 miles. As the wolf population continues to grow, they’ll likely spread out, which is concerning for wolf packs outside the exclusion area.

13. How real is the threat to outside wolf populations?

While radiation-induced mutations have been shown to pass down generations in other species, it remains to be observed in wolves. It’s certainly plausible that mutations could be passed on, but the logistics of travel for mutated wolves pose other problems.

Wolf in snow, wolf population increasing, Chernobyl
(Getty Images)

Most mutations are harmful, which means wolves that are heavily impacted by radiation are less likely to breed with other wolves—and also less likely to survive the long journey outside the exclusion zone.

However, scientists are concerned that since there’s evidence of the exclusion zone becoming a population “source” for wolves (a habitat with abundant resources that encourage population growth), there’s a real chance of genetic damage being passed down and eventually spread to outside populations. Much more research is needed to adequately assess the situation.

14. The roaming radioactive puppies

They may be man’s best friend, but they seem to be doing fine without us.

One of the more famous examples of animals adapting to the fallout are the stray dogs left behind during the evacuation. Generations of wild dogs have been born in the exclusion zones, forming their own community relatively unassisted by humans.

Stray puppies play in an abandoned, partially-completed cooling tower inside the exclusion zone at the Chernobyl nuclear power plant on August 18, 2017 near Chernobyl, Ukraine.
(Photo by Sean Gallup/Getty Images)

You can read heart-wrenching accounts of families being forced to evacuate without their beloved pets—what’s worse is that many of the dogs were shot by squads of soldiers that were dispatched into the area to try to curb the spread of contamination. However, they weren’t able to kill them all: the stray dogs that populate Chernobyl are the evidence. Many of the animals in Chernobyl migrated in the years after the incident—the dogs are truly native.

15. Stray-dog rescue

Survival is difficult for the stray dogs of Chernobyl. The Ukrainian winters are notoriously harsh, and the canines have to deal with predators like wolves and bears, as well as find their own food. The high level of radiation also affects their life span—few pups reach more than six years of age. But the clever pups have found ways to adapt.

Marie-Louise Chenery, volunteer with The Dogs of CHORNOBYL initiative, tends to stray puppies near the Chernobyl nuclear power plant.
(Photo by Sean Gallup/Getty Images)

Dogs on the outskirts of the exclusion zone will gather near the local cafe to beg for scraps from visitors and forage through the trash.

The U.S. nonprofit Clean Futures Fund provides veterinary clinics in the area, including one in the power plant. They provide vaccinations and neuter the strays in hopes of limiting the population to a manageable size.

16. Petting the dogs is discouraged, but probably not too bad for you

So, can you pet the puppies? Though mammals like canines contain radioactive materials in their fur, many tourists and employees are willing to take the risk. Scientists warn that if you pet the puppies, you should wash your hands shortly after. There is little chance of harm from the radiation, but there are other reasons why petting the animals is risky.

Administration worker Lyudmila Ivanovna greets stray puppies inside the exclusion zone at the Chernobyl nuclear power plant.
(Photo by Sean Gallup/Getty Images)

Just like with wild and feral dogs anywhere in the world, there’s risk of rabies. Veterinarian efforts seek to vaccinate all the pups against the deadly disease—but it’s an uphill battle. Regardless, volunteers and organizations are working to improve life for the dogs.

17. It will be a long time before (most) humans return

The animal populations that enjoy the lack of homo sapien interference will likely continue to live undisturbed for a while—a really long while. Scientists warn that much of Chernobyl will be unsuitable for humans to live in for at least 20,000 years!

Some people live illegally in the villages around the power plant.
(Photo credit: GENIA SAVILOV/AFP/Getty Images)

Despite the risks, a small number of villagers have returned to their former homes. Approximately 150 people now live in the area—even though the Ukrainian government forbids it and prolonged exposure to radiation has proven links to increased risk of thyroid cancer. They are able to gain access to electricity and gas, though there is no running water or sewage system.

18. Biodiversity in Chernobyl

Despite the emission of 4,000 times the radiation that was released in the nuclear bombing of Hiroshima, a great variety of species of insects, bacteria, and fauna have thrived. Cameras set up by the TREE project (TRansfer-Exposure-Effects), led by the UK’s Centre for Ecology and Hydrology, have revealed abundant levels of fauna throughout the exclusion zone—even in areas with the heaviest radiation.

A dog is seen next to a sign of radioactivity set in front of a crucifix in the ghost city of Prypyat near Chernobyl Nuclear Power Plant.
(Photo credit: SERGEI SUPINSKY/AFP/Getty Images)

Though studies show insects that have been subjected to the worst of Chernobyl’s radiation effects tend to have a shorter life span, they also revealed that this hasn’t negatively affected the overall population of the species. In other words, they don’t live as long but are able to reproduce at a high enough rate to counteract their shortened lives.

19. Radiation poisoning is still a problem for animals

Though it can be tempting to look on the bright side of the situation for wildlife populations, it’s important to remember that in most cases, the animals are thriving in spite of a catastrophic situation and not because of it.

Stray dogs hang out near an abandoned, partially-completed cooling tower at the Chernobyl nuclear power plant on August 18, 2017 near Chornobyl, Ukraine.
(Photo by Sean Gallup/Getty Images)

Much of the reason why certain populations have been able to maintain their size or even grow is hypothesized to be due to the fact that many of their natural predators and competitors were wiped out by the disaster.

While adaptations that make wildlife more resistant to radiation have been reported by scientists studying Chernobyl, the inability to reproduce the effects in a controlled environment casts doubt on their conclusions.

20. Chernobyl bird brains are smaller

A 2011 study concluded that low levels of radiation has a significant effect on brain development in birds. They performed the study by capturing 550 birds from a variety of different species and measuring the size of their brains. They found that many of the birds from Chernobyl had smaller brains than the control group.

Bird in the exclusion zone
(Photo by Firef7y/Wikimedia)

Younger birds exhibited the greatest difference in brain size, leading scientists to believe that one of the effects of the reduction in brain size is decreased cognitive ability; smarter birds with larger brains live longer than those with the genetic deformity. Because of this, the mutation will likely not pass on through future generations.

21. How radiation affects species

Radiation poisoning has had some alarming effects on wildlife. Scientists have observed higher rates of albinism and other genetic alterations in some bird species within the exclusion zone, and insects are more affected by parasites when in areas with higher radiation. Needless to say, none of this is good. 

Tawny Owls have returned to the exclusion zone.
(Photo by Arterra/Universal Images Group via Getty Images)

Invertebrate populations—such as various species of butterflies, grasshoppers, and spiders—have declined greatly within the exclusion zone, likely due to the fact that they lay their eggs on the top layer of soil, which still shows high levels of radioactivity over 30 years after the accident.

Of course, there are many disturbing observable mutations in mammals as well.

22. Short-term vs. long-term effects of radiation

Farmers near Chernobyl observed many disturbing genetic and physiological mutations in the year following the disaster. Animals born too small, with too many legs, or deformed facial features were commonly reported. In 1989 and 1990, another drastic increase in the reports of similar livestock mutations were observed—likely due to more radiation being released from the “Elephant’s Foot,” the name given to the highly radioactive remnants of the melted reactor and its housing.

Checking livestock radiation, Chernobyl
(Photo credit: VIKTOR DRACHEV/AFP/Getty Images)

Despite the negative short-term effects, long-term studies on the effects of radiation on different species seem to demonstrate that animals are more resistant to radiation poisoning than scientists thought. This is evidenced by the thriving wildlife in the exclusion zone.

23. What do we know about the way radiation causes mutations?

Mutations caused by radiation fall into two categories: There are germ line mutations in the DNA of sperm or eggs that can be passed to future generations, and there are mutations that affect cellular DNA that cause cancer, which is typically not passed down.

Elk, family, future generations
(Photo by Uwe Zucchi/Picture alliance via Getty Images)

The lack of a control group makes it difficult to study the level at which exposure to radiation causes these mutations—but scientists from the World Health Organization estimate that an additional 4,000 human deaths due to cancer can likely be attributed to the disaster at Chernobyl. As for animals, germ line mutations appear to be tapering off as certain areas become less contaminated.

24. Generational mutations in bugs could be troubling

You won’t see giant, monstrous bugs in Chernobyl, and a spider bite won’t give you special abilities, but there are still some concerns when it comes to the well-being of insects, arachnids, and other invertebrates. If the life span of these bugs are shortened for future generations, it could have grave consequences for the ecosystem.

Dragonfly populations, bugs, Chernobyl
(Photo by Sergei Chuzavkov/SOPA Images/LightRocket via Getty Images)

Dragonflies, butterflies, spiders, and grasshoppers have lower populations inside the exclusion zone. More rigorous studies are needed to observe the effect this has on other species and how the bugs may adapt to the conditions. There’s very little research as to how evolution works in a contaminated ecosystem.

25. Adaptations to contamination

It’s only been 33 years since the deadly nuclear disaster—but scientists speculate that certain animal species have already shown evolutionary adaptations. For example, frogs observed in the highly irradiated exclusion zone are a darker shade of green than those outside the area, which suggests they have adapted their exterior to become more resistant to radiation.

Tree frogs are darker in the exclusion zone
(Photo by Arterra/Universal Images Group via Getty Images)

The French National Centre for Scientific Research in Paris, France has also observed higher levels of antioxidants being naturally produced by certain bird species, suggesting they have been able to naturally adapt to a decidedly unnatural habitat—without the genetic damage usually observed when studying adaptation.

26. How radiation enters the animals

Animals ingest radioactive material by eating. Mushrooms and other fungi soak up much of the radiation in the soil. When they are consumed by small animals, the radiation passes to the animal, and then up the food chain when they are eaten by a predator or scavenger.

Bank vole eating, consume radiation, Chernobyl
(Photo by Prisma Bildagentur/Universal Images Group via Getty Images)

Radiation is higher in certain areas of the exclusion zones than others. This gives more mobile animals like wolves and deer respite from concentrated poisoning, since they are able to move about freely. In theory, the animals will naturally avoid the more irradiated areas. Researchers have said that wolves are more densely populated in Chernobyl than in Yellowstone.

27. Plants are showing adaptations

Scientists believe they may have made an incredible discovery in Chernobyl: It seems certain plants may have a natural ability to cope with high levels of radioactivity. Unlike animals, insects, and other species, plants aren’t able to flee when their environment is harmed—they either adapt or die.

Soybean mutations, radiation resistant
(Photo credit: DEREK R. HENKLE/AFP/Getty Images)

Scientists planted soybean and flax in a highly contaminated area of Chernobyl, allowed them to grow, and studied their seed proteins. They found that both types of plants were able to adapt equally, though with completely different methods. Researchers observed more cell signaling in the flaxseeds (activity that governs the behavior of cell actions when responding to their microenvironment), while in the soybean they observed increased movement of seed storage proteins—similar to how plants adapt to the introduction of more heavy metals.

28. Wildfires are a radioactive nightmare

The forest in the area surrounding Chernobyl has been largely left alone by forest management efforts. This has allowed excess debris such as litter and deadwood to accumulate, making certain areas extremely vulnerable to wildfire. The earth’s rising temperature due to climate change also poses a significant added risk.

A Ukrainian airplane drops water onto a forest fire in the Chernobyl Exclusion Zone.
(Photo by Ukraine Ministerial Cabinet Press Bureau/Anadolu Agency/Getty Images)

Wildfires are a great way to spread radiation. Radioactive materials that have been absorbed by plants are released as they catch fire—the smoke then carries the material for miles. In 2010, a wildfire in Chernobyl spread radioactive substances thousands of kilometers throughout Europe. Scientists warn that a big enough fire in Chernobyl could spread radiation all the way to Britain. It goes without saying that this can have severe, devastating consequences for both humans and wildlife.

29. Lack of humans vs. radiation

Chernobyl is a unique place to study wildlife. Not only is it absent of humans and contaminated by radiation, it’s also a place where humans used to live and no longer populate. It’s hard to ascertain how many of the changes in the environment—and the positive or negative differences in the well-being of populations—are due to the disaster itself, and how much is due to the absence and intervention of humans.

Red Forest, radiation sign
(Photo by Jorge Franganillo/Wikimedia)

For example, the Red Forest trees (called that because of the color that was left on the trunks following the disaster) that died following the disaster were replaced with deciduous trees (trees that shed leaves), which changed the landscape of the forest. The fallen leaves from these trees have a higher level of acidity than what is observed outside the exclusion zone. This greatly changes the makeup of microorganisms in the area. Scientists point to this as an example of how both human intervention and natural adaptations are changing the ecosystem.

30. For wildlife, the benefit of human absence likely outweighs the negative effects of radiation

It’s a bit depressing, but researchers have long observed that without humans around, wildlife almost always fares better. Chernobyl is no exception. There’s some debate as to how well wildlife is thriving within the exclusion zone vs. the outside area, but many scientists theorize that animal populations have moved further into the contaminated area to escape human interference.

Checking radiation level of shoes, Chernobyl
(Photo by Pavlo Gonchar/SOPA Images/LightRocket via Getty Images)

Free from the typical negative human impact on their habitat, food supply, and population due to hunting, radiation poisoning seems a small price to pay for many animals. We’ve long known the harm radioactivity imposes on animals, but it seems to be less disastrous in the long term when compared to typical human sprawl.