Lizard hunting styles impact ability to walk, run

Foraging sheds light on evolution of biomechanics

Scientists studied lizard walking and running mechanics on a race track with a built-in force plate. Click here for more information.

ATHENS, Ohio (April 21, 2008) — The technique lizards use to grab their grub influences how they move, according to researchers at Ohio University.

A research team led by doctoral student Eric McElroy tracked 18 different species of lizards as they walked or ran in order to understand how their foraging styles impact their biomechanics. The study, funded by the National Science Foundation, was featured in the April 1 edition of the Journal of Experimental Biology.

Lizards use two basic foraging techniques. In the first approach, aptly dubbed sit-and-wait, lizards spend most of their time perched in one location waiting for their prey to pass. Then, with a quick burst of speed, they run after their prey, snatching it up with their tongues.

In the other form of foraging, known as wide or active foraging, lizards move constantly but very slowly in their environment, using their chemosensory system to stalk their prey, according to the research team, which included McElroy’s adviser Stephen Reilly, professor of biological sciences, and undergraduate honors thesis student Kristin Hickey.

Although wide foraging evolved from the sit-and-wait technique, these two styles are almost opposites. Some wide foragers are on the move about 80 percent of the time while sit-and-wait foragers may move only about 10 percent of the time, said Reilly, co-author of a recent book on the topic, Lizard Ecology, published by the Cambridge University Press.

While all lizards have the ability to run, a predatory defense mechanism, the study found that sit-and-wait lizards won’t walk. Lizards that use the sit-and-wait method of foraging use running mechanics even when moving at slower speeds.

Wide foragers, however, evolved a walking gait and mechanics. They must move at slower speeds in order to use their advanced chemosensory system to locate their prey.