Sticky toepads have independently evolved in geckos, skinks and Anolis lizards -- producing tree acrobats specially adapted to life in the forest canopy. Scientists have long considered sticky toepads an ‘evolutionary key innovation’ that allow arboreal lizards to interact with the environment in ways that many padless lizards cannot.

 

Yet, some lizards without toepads have adopted the canopy lifestyle, an observation that has puzzled scientists for decades. Biologists Aryeh Miller and James Stroud at Washington University in St. Louis set out to find if lizards with toepads had an evolutionary advantage for life in the trees relative to their padless counterparts.