The frogs are among several species that have undergone genetic mutation in Chernobyl.
The explosion at Chernobyl nuclear power plant is one of the worst industrial disasters in history. After the meltdown in 1986, the area was abandoned by humans. But many animals remained in the 'Chernobyl Exclusion Zone' - a 30-mile cordon where public access was forbidden due to contamination. There were fears that all life will die in the region due to radiation, but in the past few decades, many species have actually thrived adapting to the unique threat. Several studies have shown that these animal have begun to display differences from those elsewhere, with some of them developing distinct characteristics.
In 2016, researchers Pablo Burraco and German Orizaola began examining the way that eastern tree frogs were responding to radiation in the Chernobyl area, as per Discover Magazine. Normally, these frogs are bright green in colour, but in the area around the nuclear plant, their skin turned black.
Researchers discovered that the melanin responsible for this dark colour in various species can actually temper some of the negative effects of ultraviolet radiation.
The discovery intrigued the two researchers, who expanded it to analyse the skin colour of frogs captured from 12 ponds, including in areas that were most radioactive. In all, the researchers analyzed more than 200 frogs and found that those from high radiation areas are much darker on average, said Discover Magazine.
In the same year, Tim Mousseau, a biologist at South Carolina University, published a review of 17 cases, which included everything from pine trees to grasshoppers and voles. They found that the bacteria on Chernobyl swallows is more resistant to damage caused by the induced radiation.
Last year, a study published in Science Advances gave a glimpse into how long-term radiation exposure affects living beings. The wild dogs living in the area underwent genetic mutation, the research team found.
They said that dogs from the power plant and Chernobyl City are genetically distinct, as per an ABC News report. The team added that more research will reveal how much radiation contributed to the genetic differences.
Earlier this month, a study found that wolves living in the Chernobyl Exclusion Zone have altered immune systems and developed the ability to fight cancer. These animals, which are different from their counterparts outside the region, could prove to be the key in helping humans fight the deadly disease, the study further said.
As per IFL Science, the CEZ wolves were exposed to 11.28 millirem of radiation daily - more than six times the legal safety limit for humans.