May I have your attention, please?
The lizard species Anolis gundlachi performs eye-catching push-ups to get the attention of nearby lizards, shows a study appearing online November 24 in Proceedings of the National Academy of Sciences. These yellow-chinned anoles stake territorial claims by bobbing their heads and inflating a colorful pouch on their necks, usually while perched on a tree branch or trunk. But when conditions are poor, as they might be, for example, on a blustery, cloudy day, the lizards do four-legged push-ups to better ensure neighbors are watching. Only then do they launch into the bobbing and inflating.
Study authors Terry Ord, then at the University of California, Davis, and Judy Stamps, also of UC Davis, constructed robot lizards that perched on the sides of trees in deep-shade forests of northeastern Puerto Rico. The robots mimicked the Anolis messages, both with and without the push-ups, and the researchers measured the time elapsed before real lizards of the same species looked at the robot. In poor conditions, other lizards were much more likely to receive the message when it was preceded by a few attention-grabbing push-ups. Ord likens the push-ups to someone tapping a fork against a glass before launching into a lengthy speech. “The glass-tapping does nothing but get attention,” and once that is achieved, the real message starts, says Ord, now at Harvard University. — Laura Sanders