Use of vibratory cues for detection of insect prey by the sandswimming lizard Scincus scincus

Abstract

The sandfish lizard, Scincus scincus, inhabits the Sahara Desert and spends most of its time buried in the sand. Laboratory experiments were performed to determine if Scincus can respond and orient to insects on the sand surface by detecting vibrations produced by movements of the insects. When buried, Scincus can detect and respond to crickets and mealworms moving over the surface at distances up to about 15 cm. These responses were guided by vibratory cues, not olfactory cues, as the lizards responded much less frequently to dead insects placed on the surface at equal distances. The lizards obtain directional information from the vibrations, and can localize the insects, orient toward them, and emerge from the sand to capture them. When walking on the surface of the sand, Scincus often displays a peculiar behaviour of plunging its head into the sand. Experiments determined that this behaviour aids lizards in detecting vibrations produced by insects moving through the sand, and presumably facilitates transmission of sand-borne vibrations to the inner ear.