

Bisons are seen at a bison nursery in the exclusion zone around the Chernobyl nuclear reactor near the abandoned village of Dronki, Belarus, January 28, 2016.

Vasily Fedosenko/Reuters

The Chernobyl nuclear power plant in the then-Soviet Union experienced a power surge in April 1986.

Residents of the surrounding areas were evacuated, and the area has turned into a ghost town in the decades since, save for a few locals that returned.

But a diverse community of wildlife has since repopulated the area thanks to the absence of humans.

Visit Business Insider's homepage for more stories.

Related Video: These Inventions Can Help Save the Earth

On April 26, 1986, reactor number four at the Chernobyl nuclear power plant, located in the then-Soviet Union, experienced a power surge, resulting in an explosion that sent a cloud of radioactive materials across parts of Europe.

It was the world's worst nuclear accident. Around 350,000 people were evacuated following the explosion.

Today, the areas surrounding the Chernobyl nuclear power plant are almost completely void of humans, save for a number of locals that reside in the Chernobyl exclusion zone.

But the contaminated area is now populated by a diverse wildlife community.

Scientists and researchers are still investigating how exactly the animals are affected by radioactive exposure, but many studies so far point to the most likely explanation for why the animals are thriving: the lack of humans.

"Nature flourishes when humans are removed from the equation, even after the world's worst nuclear accident," Jim Smith, an environmental scientist who has studied life near Chernobyl, told National Geographic.

Here's how nature has reclaimed the contaminated land.



The nuclear explosion at the Chernobyl Nuclear Power Plant in 1986 sent plumes of radioactive contaminants across parts of Europe.





The Chernobyl nuclear power plant in April 1986, taken just days after the explosion.

AP

Source: Business Insider



As a result, about 350,000 people in the exclusion area were forced to leave their homes, most of them forever.





People were told to take few personal belongings and identity papers, as it was thought they would be returning several days later, which was not the case.

Igor Kostin/Sygma/Contributor

Source: Business Insider



The areas surrounding the plant are now considered to be some of the most polluted areas on the planet. A 1,000-square-mile Chernobyl Exclusion Zone is now the officially designated exclusion zone in Ukraine ...



Story continues

Chernobyl Exclusion Zone

Google Maps/Andrew Blackwell/Business Insider

Source: visitchernobyl.com , BBC, USA Today



... which adjoins the exclusion zone in neighboring Belarus, known as the Palieski State Radioecological Reserve. Though the explosion took place in Ukraine, much of the radiation from the Chernobyl disaster was blown north to Belarus.



exclusion zones

Google Maps/Andrew Blackwell/Business Insider

Source: The Guardian



The Chernobyl exclusion zone is still considered an unsafe region for humans due to the high levels of radiation. It's technically considered illegal to live there, though there are some who do.





A photo of Ivan Semenyuk, a resident of the exclusion zone, taken in 2011.

SERGEI SUPINSKY/AFP/Getty Images

Read more: Photos show what daily life is really like inside Chernobyl's exclusion zone, one of the most polluted areas in the world



Other than the small population of local residents that have returned, the empty area has been mostly abandoned ever since ...





A photo of an abandoned bumper car track is one of many in photographer David McMillan's series.

Courtesy of David McMillan

Read more: A photographer visited the abandoned towns around Chernobyl more than 20 times over the past 25 years, and the captivating photos show just how suddenly time stopped in its tracks after the disaster



... with the exception of the descendants of abandoned animals and a somewhat newly developed wildlife population.





An elk in the exclusion zone around the Chernobyl nuclear reactor in 2016.

Vasily Fedosenko/Reuters

Source: Business Insider



When people were evacuated from Chernobyl in 1986, many left their pets behind thinking that they would soon return. After they were unable to return, Soviet Army soldiers were sent to kill the pets that had been left behind.



Chernobyl stray dog

viktor95/Shutterstock

Source: SPCA International, Clean Futures Fund



But some of the pets survived, and now hundreds of their descendants live in the exclusion zone.





Stray dogs in the exclusion zone.

Sergiy Romanyuk/Shutterstick

Source: SPCA International, Clean Futures Fund



The Clean Futures Fund (CFF), which has been visiting Chernobyl to spay, neuter, and vaccinate stray dogs, estimates that there are more than 600 stray dogs throughout the exclusion zone. SPCA International (SPCAI) estimates that it has provided care fore more than 800 dogs and cats living there.





Stray puppies play in an abandoned cooling tower at the Chernobyl nuclear power plant in 2017.

Sean Gallup/Getty Images

Source: SPCA International, Clean Futures Fund



While there are many of these stray animals in the exclusion zone, SPCAI and CFF report that most of them struggle to survive there. They rely on the care and scraps of power plant workers and occasional visitors, and few live to be more than six years old.





Lucas Hixson, cofounder of CFF, strokes a stray dog near the Chernobyl power plant in 2018.

Sergei Supinsky/AFP/Getty Images

Source: SPCA International, Clean Futures Fund



The organizations are working together to continue caring for these animals, and in 2018, they adopted out 15 puppies that didn't pose a radiation risk to humans.



Stray puppies Chernobyl

Sean Gallup / Getty Images

Source: SPCA International, Clean Futures Fund



Stray pets aren't the only animals proliferating in the exclusion zone. Scientists say it's possible that the number of wild animals in the area is now higher than it was 33 years ago.





Elk is seen in the exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: Business Insider



Today, you can find elk, deer, wolves, bison, foxes, and dozens of other species roaming the area.





Bison is seen in the exclusion zone in 2011.

Vasily Fedosenko/Reuters

Source: Business Insider



The European brown bear — an animal that hadn't been seen in the region in over a century — has also been documented living in the zone.





The exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: Telegraph



And you can even find the endangered Przewalski's horse, a rare wild horse species, roaming the area.





Przewalski's horses near the city of Tabor, Czech Republic, in 2017. This photo was not taken in the Chernobyl Exclusion Zone.

David W Cerny/Reuters

Source: BBC



Scientists purposefully released them in the area in the 1990s as part of a conservation program. They travel in herds and seem to have adapted well to the environment, according to the University of Salford's Mike Wood.





Przewalski's horses near the city of Tabor, Czech Republic, in 2012. This photo was not taken in the Chernobyl Exclusion Zone.

David W Cerny/Reuters

Source: BBC



But there is debate about exactly why the contaminated zone has proven to be a beneficial environment for animals.





A viper is seen in the exclusion zone in 2009.

Vasily Fedosenko/Reuters

Source: Business Insider, National Geographic



And there's also debate about exactly how much the wildlife population is "thriving" inside the zone compared to populations outside of it.





A wolf is seen in the exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: Business Insider, National Geographic



Scientists are trying to understand just how much wildlife inside the exclusion zone is benefiting from the lack of human interference and how much it is suffering from the contamination in the zone.





A tawny owl is seen in the exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: Reuters



The lingering radiation is unhealthy for wildlife, but some scientists say the effects of human activity — like hunting, farming, and forestry — are worse on the animals.





A magpie is seen in the exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: Live Science, National Geographic



Some researchers think that wildlife has come to the area because it has been almost completely untouched by humans, which has allowed certain species to thrive.





An otter is seen in the exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: Live Science



Because hunting isn't a common practice within the zone, large mammals are more likely to live and thrive in this area than smaller mammals, according to some scientists.





Bison is seen in the exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: Live Science, National Geographic



Bison, in particular, are thought to benefit from the reduced human population.





Bison is seen in the exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: National Geographic, Business Insider



But there are still ongoing studies to find out if radiation has a negative effect on animals to the point where it would harm or kill them.





A fox is seen in the exclusion zone in 2018.

Tijuana2014/Shutterstock

Source: National Geographic



Populations of animals live across different areas within the zones, where levels of contamination vary.





A radiation sign is seen in the exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: BBC



So scientists are also studying how radiation exposure levels change in animals as they travel throughout the different areas within the zone.





Elks is seen in the exclusion zone in 2009.

Vasily Fedosenko/Reuters

Source: Telegraph and BBC



Studies have shown that smaller animals, like birds and rodents, have exhibited poor health effects, like tumors and cataracts, which are common side effects of radiation exposure.





A black grouse is seen in the exclusion zone in 2011.

Vasily Fedosenko/Reuters

Source: National Geographic



Smaller animals exposed to radiation have also exhibited abnormal growth developments.





A woodpecker is seen in the exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: National Geographic



Studies have shown that some insects living in highly radioactive areas also have shorter lifespans and are more susceptible to parasites.





A spider web is seen in the exclusion zone in 2009.

Vasily Fedosenko/Reuters

Source: Business Insider



And higher levels of albinism and genetic alterations have been found in birds living in areas with higher contamination levels.





A long-eared owl is seen in the exclusion zone in 2009.

Vasily Fedosenko/Reuters

Source: Business Insider



But there is still a vast bird population, with some 200 bird species living in the exclusion zone.





A white-tailed eagle is seen in the exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: Business Insider



So even though studies have shown that radiation negatively affects some individual creatures, some scientists say that the overall population densities are unaffected.





A white-tailed eagle is seen in the exclusion zone in 2009.

Vasily Fedosenko/Reuters

Source: Business Insider



According to German Orizaola, a zoology researcher who has studied the effects of radiation on tree frogs in Chernobyl, this could mean that animals have a higher resistance to radiation than we previously believed.





A deer is seen in the exclusion zone in 2009.

Vasily Fedosenko/Reuters

Source: Business Insider



It's possible that some animals are adapting to the radiation they are exposed to.





Elk is seen in the exclusion zone in 2008.

Vasily Fedosenko/Reuters

Source: Business Insider



Researchers are studying the kinds of mutations that radiation exposure is causing in certain species.





A raven is seen in the exclusion zone in 2008.

Vasily Fedosenko/Reuters

Source: National Geographic



For example, one group of researchers working with Orizaola found that frogs within the exclusion zone are darker in color than frogs inhabiting areas outside of it.





A yellowhammer is seen in the exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: Business Insider



Studies in certain animals, like barn swallows and voles, suggest that the mutations may even be passed down to the next generation.





A yellowhammer is seen in the exclusion zone in 2009.

Vasily Fedosenko/Reuters

Source: National Geographic and International Journal of Science



Mutations among the large wolf populations within the zone are also being explored.





A wolf is seen in the exclusion zone in 2008.

Vasily Fedosenko/Reuters

Source: National Geographic



Wolves are one of the most prominent species residing within the exclusion zone.





Wolves are seen in the exclusion zone in 2009.

Vasily Fedosenko/Reuters

Source: National Geographic



Scientists have found that the population of wolves is seven times greater in the Belarussian part of the Chernobyl zone than in comparable, uncontaminated reserves.





A wolf is seen in the exclusion zone in 2016.

Vasily Fedosenko/Reuters

Source: Reuters, National Geographic



Jim Beasley, a wildlife ecologist at the University of Georgia in the US, told National Geographic in 2016 that the wolves in the Chernobyl exclusion zone may outnumber the wolf population at Yellowstone National Park.





A wolf is seen in the exclusion zone in 2008.

Vasily Fedosenko/Reuters

Source: National Geographic



Scientists tracked one of these wolves from the Chernobyl exclusion zone all the way to Russia, which Beasley told National Geographic in 2018 isn't surprising, since many young male wolves will make long treks in search of mates.





A wolf, not the exact animal referenced, is seen in the exclusion zone in 2008.

Vasily Fedosenko/Reuters

Source: Independent and National Geographic



But the findings of the wolf's journey posed the question of whether or not potential mutations in its species could actually be spread to other wolf populations outside of Chernobyl.





A wolf in the exclusion zone in 2008.

Vasily Fedosenko/Reuters

Source: National Geographic



But seeing as how the wolf was physically capable to make that 250-mile journey, and that mutational effects are usually harmful, Anders Moller, a scientist at the University of Paris-Sud, told National Geographic that that's unlikely.





A wolf in the exclusion zone in 2009.

Vasily Fedosenko/Reuters

Source: National Geographic



Though Tim Mousseau, a biologist at the University of South Carolina, told National Geographic in 2018 that the spread of mutations from Chernobyl wolves is "certainly plausible" since smaller animals have been found to have that potential.





Wolves' footprints are seen in the exclusion zone in 2009.

Vasily Fedosenko/Reuters

Source: National Geographic

This is an updated version of an article originally written by Courtney Verrill.

Read the original article on Business Insider