Antipredatory Threat Displays and Aggressive Defenses by the Acrodont Lizard Uromastyx aegyptius (Acrodonta: Agamidae: Uromasticinae) when Cornered and in Crevices

Abstract

The dhub, a large acrodont lizard from northern Africa and the Arabian Peninsula, relies strongly on escape into burrows used as refuges when possible. In the laboratory we studied how these lizards defend themselves against human beings serving as simulated predators when the lizards are unable to escape into refuges or are pursued into refuges. When pursued into a corner or overtaken when unable to could enter refuges, dhubs performed impressive threat displays. When fleeing proved ineffective, the lizards performed various combinations of the following behaviors: opening their mouths, hissing, arching their backs upward, tilting their bodies toward the pursuing investigator, inflating their bodies, performing repeated sinuous undulations of the body along its longitudinal axis, and sweeping the heavily armed tail or both the head and tail toward the investigator. The displays appeared quite threatening and dhubs can deliver powerful bites and strong blows with the heavy, spinous tail. When approached while in crevices, dhubs pressed body parts against the crevice roof or wall while holding the tail free of the wall. Most individuals used the tail to lash at the investigator, but few exhibited any of the defensive display behaviors used outside crevices. Thus, dhubs have distinct defensive behaviors inside and outside refuges. They use refuges when possible, employ threatening and startling displays as well as physical defenses when overtaken outside refuges, and when confronted within refuges wedge the body against walls to make extraction more difficult while blocking access to the body and defending themselves by blows delivered by the tail.