This frog’s behavior seems weirdly stupid. But there’s actually a wisdom of sorts in swallowing a Christmas light–if you’re a Cuban tree frog, that is. For thousands of years, the only glows your ancestors ever saw on a tree came from luminescent insects. If they responded to a little glow by attacking, they got a meal. They were more likely to survive and have baby frogs. The frogs that didn’t respond? Some of them may have done just fine. But others may have gone hungry. The males might have struggled to attract a mate; the females might have laid small eggs that failed to develop.
Natural selection laid down this response in Cuban tree frogs, in other words. Christmas lights have only recently come into their lives, and natural selection has shown no sign yet of striking the “attack glowing light” behavior off the menu.
Snyder’s glowing frog is one of the prettiest examples of a surprisingly common thing that happens when animals come into contact with humans. We have altered the environment in a vast number of ways, both small and large. And when animals try to read the cues from our human environment, they can get tricked. They can end up doing something that kills them, loses them the opportunity to reproduce, or simply wastes their time. Scientists call these situations evolutionary traps.