Rival packs of stray dogs scavenging for scraps around the Chernobyl fallout zone may be evolving faster than other animals to survive in one of the most hostile environments on Earth.
Scientists are analysing the impact of the world's worst nuclear disaster 36 years ago on semi-feral canines that roam the decaying, abandoned buildings of the power plant and the surrounding radioactive Red Forest.
Miraculously, the wild dogs are still able to breed and endure extreme winters while relying on scraps from tourists who are warned not to touch them.
Researchers say humans can learn from the resilience of the some 500 stray dogs whose numbers have increased in the 36 years after the cataclysmic accident and Soviet coverup.
On April 26, 1986, an explosion and fire at the Chernobyl power plant in Ukraine caused radioactive fallout to spew into the atmosphere. Thirty workers were killed while the long-term death toll from radiation poisoning is estimated to number in the thousands.
The packs are thought to be descendants of dogs left behind by families during the chaotic evacuation. They are thought to have survived attempts by Soviet soldiers to shoot the animals to prevent the spread of radiation.
"Somehow, two small populations of dogs managed to survive in that highly toxic environment," head researcher Dr Norman Kleiman said.
Blood samples were collected from the semi-feral dogs captured around the power plant and another pack operating in nearby Chernobyl City.
Despite sharing breed makeups with German shepherds and being separated by only ten miles, the free-breeding dog populations were found to be reproducing independently of each other.
By analysing the dogs' DNA, the team identified 391 outlier regions in their genomes that differed between the two groups with some pointing to genetic repair after exposures similar to Chernobyl.
Scientists maintain there is still work to be done to evaluate how decades of radiation exposure may have altered animals' genomes -- and even, possibly, sped up evolution.
They hope future studies will reveal the genetic effects of exposure to radiation and observe adverse health effects of other nuclear or environmental disasters on both animals and humans.
According to Dr Matthew Breen from NC State: "The overarching question here is: does an environmental disaster of this magnitude have a genetic impact on life in the region?
"By teasing out whether or not the genetic changes we detected in these dogs are the canine genome's response to the exposures the populations have faced, we may be able to understand how the dogs survived in such a hostile environment and what that might mean for any population -- animal or human -- that experiences similar exposures."
Swedish authorities were the first to detect radioactive fallout in Europe, forcing Soviet officials, who had attempted to cover up the disaster, to open up about it days later.
In 2017, a state veterinary agency in the Czech Republic said about half of all wild boars in the country's southwest were radioactive and considered unsafe for consumption. The boars feed on an underground mushroom that absorbs radioactivity from the soil. Similar problems with radioactive wild animals were reported in Austria and Germany.
The full study on the Chernobyl dogs was published in the journal Canine Medicine and Genetics.