Credit: Share Imagine discovering that an animal species you thought had gone extinct was still living — without even laying eyes on it. Such was the case with the Brazilian frog species Megaelosia bocainensis, whose complete disappearance in 1968 led scientists to believe it had become extinct. But through a novel genetic detection technique, it was rediscovered in 2020. Such discoveries are now possible, thanks to a new approach that recovers and reads the trace amounts of DNA released into the environment by animals. It’s called environmental DNA, or eDNA — and it takes advantage of the fact that every animal sheds DNA into its environment via skin, hair, scales, feces or bodily fluids, as it moves through the world.