Male yellow-chinned anoles often do pushups to communicate with other lizards, according to a new study. A group of U.S. researchers traveled to Puerto Rico to study the lizards, which performed the exercise in low-visibility conditions to gain the attention of the lizards they wanted to send a territorial message to.

The anoles typically claim a spot on a tree trunk by bobbing their heads and puffing up the brightly-colored skin under their throats. But this signal can often be obscured by dense vegetation and poor lighting. Researchers found that anoles performing pushups dramatically increased the message's effectiveness in these conditions.

The researchers made the discovery by building a hand-painted robot that resembled an anole. They placed it on a tree trunk and programmed it to display both with and without pushups before conveying its territorial message. "With pushups, the lizards would orientate toward the robots within the first one or two movements of the alert display," says Dr. Terry Ord, researcher at Harvard University and the University of California-Davis and the lead author of the study.