Mutant creatures living in the Chernobyl exclusion zone

Some animals in Chenobyl became strange after the 1986 nuclear disaster .

On April 26, 1986, an explosion at the Chernobyl nuclear power plant in Ukraine released radioactive dust into the atmosphere. Thirty workers died immediately after the disaster, but in the long term, the death toll from radiation poisoning is estimated to be in the thousands. According to a report by the European Parliament, the explosion released 400 times more radiation into the atmosphere than the Hiroshima atomic bomb, and nuclear fallout also fell over a large area of ​​Europe. This is considered the world's worst nuclear disaster.

The former Soviet Union quickly established ^a 2,700km2 "Chernobyl Exclusion Zone" around the plant, erecting a fence with a radius of about 30km and prohibiting people from accessing it due to pollution.

Since 2011, the zone's administrators have deemed it safe to visit. Visitor numbers have steadily increased. Although some areas of the zone have high radiation levels, visiting is relatively safe if visitors follow instructions.

To this day, most of the exclusion zone remains abandoned, becoming a habitat for wild animals. So how does the radiation in the exclusion zone affect them? Scientists have conducted research and said that some animals have begun to show differences compared to animals in other places.

Black mutant frog

Skin color change of radioactive tree frog. (Photo: Evolutionary Applications).

In a study published in the journal Evolutionary Applications in 2022, radiation from the Chernobyl plant led to changes in the skin color of oriental tree frogs ( Hyla orientalis ) in Ukraine, causing their skin to turn from green to black.

"Frogs had darker skin in locations closest to the high radiation levels at the time of the disaster. Tree frogs living in the Chernobyl exclusion zone had significantly darker skin than frogs living outside," said the study's authors, including Pablo Burraco at Uppsala University.

They found that the darker coloration may not be a random mutation, but rather an adaptive response to protect the frogs from high levels of radiation. Dark coloration protects against various sources of radiation by neutralizing free radicals and reducing DNA damage, and the pigment melanin is thought to act as a buffer against ionizing radiation. Melanin is responsible for dark skin and dark eyes in many animals, including humans, but it can also reduce the negative effects of radiation.

Superpower Bacteria

Bacteria on the wings of swallows in Chernobyl were found to be more resistant to the effects of gamma radiation. When exposed to radiation, bacteria from Chernobyl were still able to reproduce and grow better than bacteria from elsewhere.

"The long-term effects of radiation in natural populations may be an important selective pressure for traits that help bacteria survive better in certain environments," according to a study published in the journal Scientific Reports in 2016. The study was conducted by Mario Xavier Ruiz-González at Paul Sabatier University and colleagues.

Wolf against cancer

Wolves roam the Chernobyl exclusion zone. (Photo: Reuters).

New research published earlier this year found that the population of wolves living in the Chernobyl exclusion zone is genetically different from their counterparts outside the zone. In particular, wolves exposed to radiation appear to have developed protective mutations that increase their survival rate when they develop cancer. The study was conducted by Cara Love, an evolutionary biologist and ecotoxicologist at Princeton University who has studied wolves in Chernobyl for a decade.

The study found that wolves in the exclusion zone were exposed to more than 11.28 millirems of radiation every day of their lives, more than six times the level allowed for human workers. The study also found that wolves had immune system changes similar to those seen in cancer patients undergoing radiation therapy. Furthermore, genetic analysis showed that a portion of the wolf genome developed resistance to cancer.

Dogs are genetically different.

Dogs roam the "ghost town" of Pripyat in the Chernobyl exclusion zone, Ukraine. (Photo: Dimitar Dilkoff/Agence France-Presse).

A 2023 in-depth DNA study of 302 stray dogs living in the Chernobyl exclusion zone found that they were genetically distinct from both purebred and free-breed dogs. The team said it appeared that most of the dogs they studied were descendants of pets that residents had to leave behind when they evacuated.

At first, the team thought the dogs had been together for so long that they might start to look alike. But through their DNA, they were able to easily distinguish between those that had lived in areas with high, low, and medium radiation exposure. Dogs provide a great way to look at how this type of environment affects mammals in general, said study co-author Tim Mousseau, a professor of biology at the University of South Carolina.