Ecology and Behaviour of Burton＇s Legless Lizard （Lialis burtonis, Pygopodidae） in Tropical Australia

Abstract

The elongate, functionally limbless flap-footed lizards (family Pygopodidae) are found throughout Australia, ranging into southern New Guinea. Despite their diversity and abundance in most Australian ecosystems, pygopodids have attracted little scientific study. An intensive ecological study of one pygopodid, Burton's legless lizard (Lialis burtonis Gray 1835), was conducted in Australia's tropical Northern Territory. L. burtonis eats nothing but other lizards, primarily skinks, and appears to feed relatively infrequently (only 20.8% of stomachs contained prey). Ovulation and mating occur chiefly in the late dry-season (beginning around September), and most egg-laying takes place in the early to middle wet-season (November-January). Females can lay multiple clutches per year, some of which may be fertilised with stored sperm. Free-ranging L. burtonis are sedentary ambush foragers, with radio-tracked lizards moving on average < 5 m/day. Most foraging is done diurnally, but lizards may be active at any time of day or night. Radiotracked lizards were usually found in leaf-litter microhabitats, a preference that was also evident in habitat-choice experiments using field enclosures. Lizards typically buried themselves in 6-8 cm of litter; at this depth, they detect potential prey items while staying hidden from predators and prey and avoiding lethally high temperatures.