It's been 40 years since the Chernobyl disaster. In 2016, evolutionary biologist Pablo Burraco from Doñana Biological Station made his first field trip to the irradiated landscape. While walking through darkness near the abandoned power plant, he heard a tiny male tree frog calling for a mate. He caught the 5cm amphibian and immediately noticed something unusual — the frog was darker than others of the same species living further away.

The discovery raised a question that has fascinated scientists since the 1986 reactor explosion: had radiation from the stricken power station changed the creatures living near it? Burraco's dark-colored frog provided the first clue. The area surrounding Chernobyl was evacuated for many miles after the catastrophic explosion, leaving wildlife to inhabit an abandoned, contaminated zone with minimal human disturbance for decades.

This finding suggests that wildlife in the Chernobyl exclusion zone has adapted in unexpected ways. Rather than being devastated, certain species may have undergone physiological changes in response to chronic radiation exposure. The discovery opens new questions about how ionizing radiation affects evolution in wild populations living in contaminated environments.