Pushing the Edge: Extended Activity as an Alternative to Risky Body Temperatures in a Herbivorous Teiid lizard (Cnemidophorus murinus: Squamata)
A combination field and laboratory study tested the hypothesis that a herbivorous lizard, Cnemidophorus murinus, extends activity at high body temperatures to digest plant material. Body temperatures (Tb) of active lizards averaged 37·2 °C and were no higher than those of insect-eating Cnemidophorus. Near constant Tb was maintained by behavioural means even though habitat temperatures varied greatly. Field-based behavioural data show that C. murinus extend activity by shifting among microhabitats to increase duration of time available at high Tb for digestion. Laboratory studies revealed large variation in selected temperatures (Tsel), but the overall average was 35·9 °C, which is lower than field Tb. By carefully selecting microhabitats and extending activity, C. murinus maintains constant high body temperatures to digest plant material without risking potentially lethal overheating.
extended activity, risky behavior, functional ecology
L. J. Vitt, J. P. Caldwell, S. S. Sartorious, William E. Cooper Jr., T. A. Baird, T. D. Baird, and V. Perez-Mellado (2005).
Pushing the Edge: Extended Activity as an Alternative to Risky Body Temperatures in a Herbivorous Teiid lizard (Cnemidophorus murinus: Squamata). Functional Ecology.19 (1), 152-158.