Field Body Temperatures and Thermoregulatory Behavior of the High Altitude Lizard, Lacerta bedriagae

Abstract

Many species of lizards are known to maintain relatively high and constant body temperatures (Avery, 1982; Huey, 1982). Their abilities to do so depend largely on regulatory behaviors that alter heat exchange with the environment and on the thermal conditions within their habitats. Ectotherms living at high altitudes (and latitudes) offer unique opportunities to study thermoregulatory responses to the rather unfavorable and strongly variable thermal characteristics of these regions. High altitude lizards often exhibit lower and more variable activity body temperatures, and/or thermoregulate less precisely than conspecific or congeneric populations living at lower elevations (Brattstrom, 1965; Hertz and Nevo, 1981; Vial, 1984; Crowley, 1985). We report here results of a short-term study on field body temperatures and aspects of thermoregulatory behavior of the lizard Lacerta bedriagae. This mediumsized lizard (adult male body size = 66-84 mm, mass = 7-14 g; adult female body size = 66-80 mm, mass = 7-11 g) is endemic to the Mediterranean islands Corsica and Sardinia, where its distribution is usually retricted to altitudes >1000 m (Schneider, 1984 reviews information on the habits of this poorly known species). We hypothesized that this lizard, living in an environment characterized by low and variable ambient temperatures, would be active over a relatively wide range of body temperatures. Our main aim therefore was to examine changes in body temperature and thermoregulatory behavior in relation to diel variations in the thermal environment.