You might be aware of one of the worst nuclear disasters that happened in the history of mankind in 1986. We are talking about the Chernobyl nuclear plant disaster in Ukraine when one of the reactors present there, exploded and thus emancipated lethal radioactive waste into the nearby areas. It has been believed that the energy released as a result of this explosion was 100 times more than that released from the nuclear bombs of Hiroshima and Nagasaki. Although human beings were rescued and transported to safe locations at the time of the incident, the wildlife present at that time in the nuclear zone was affected badly and the effects can be witnessed till now.
Many decades after this disaster, a team of Spanish researchers visited the Chernobyl Exclusion Zone in 2016 to determine the state of the surrounding plants and animals in that area. They observed that frogs in that area are not green anymore, instead they have turned black or darker in color, thus following the effects of that disaster. According to the researchers, they have transformed their coloration “in order to better mitigate the effects of radiation”. The team comprising Pablo Burraco, who is a biologist with the Doñana Biological Station in Seville, Spain, and his colleagues went to great lengths to further investigate the cause of the change in coloration.
Hence, they started their research work in which they took the coloration samples of Eastern frogs from various northern regions of Ukraine. Furthermore, around 200 male frogs were observed in different locations of the Chernobyl Exclusion Zone between 2017-2019. They were then also compared to those present outside of the exclusion zone and at last, researchers finally managed to conclude the results. They revealed that the darker color present in the frogs of the exclusion zone is due to the effects of nuclear radiation to which they have evolved.
Furthermore, the radiations were so engrossed in those frogs that now they are evolving with these marks and the effect is transferring from generation to generation. Some of them even are completely black in color, while some have certain black marks on their skin. The researchers stated, “We consider the most plausible explanation to [why] frogs within the Chernobyl Exclusion Zone [are changing color] is that the extremely high radiation levels at the moment of the accident selected for frogs with dark skin.”
In addition to this, Germán Orizaola, who is the co-author of the study, stated, “They actually did not ‘change color’, what changed was the proportion of dark versus normal/green frogs. We suppose that this happened shortly after the accident (first years), when radiation levels were much higher, and radioisotopes more diverse.” He added, “It was indeed the extraordinary selection pressure caused by ionizing radiation that directed the evolution of amphibians from green to black.”