Lizards in Florida have rapidly evolved traits that make them better tree-climbers, probably in response to an invasive competitor.

Credit: Gerry Ellis/Minden Pictures/FLPA

Cuban brown anole lizards (Anolis sagrei) have spread over the past few decades across the southeastern United States, where they compete for territory and food with the native green anole (Anolis carolinensis; pictured). Yoel Stuart at the University of Texas, Austin, and his colleagues introduced small populations of the invader to three islands in a central Florida lagoon and found that the native green anoles perched higher in trees than native lizards on nearby islands that had not been invaded. After just 20 generations of anoles, the team found that native lizards on invaded islands had evolved larger toepads, probably to help them cling to less-secure branches farther up in trees.

Competition between closely related species can drive rapid, observable evolutionary change, the authors say.

Science 346, 463–466 (2014)