The effects of thermoregulatory postures and orientation to the sun on steady-state body temperatures in the zebra-tailed lizard (Callisaurus draconoides) were determined using computer simulation techniques. The parameters evaluated for each posture included: a) silhouette area (As) as a function of solar zenith angle (Z) and relative azimuth angle (RAZ) and b) the convective heat transfer coefficient (he). Four simulations, incorporating micrometeorological data from the literature, were used to evaluate relationships between postures, orientation to the sun, micrometeorological variables and the mechanisms of heat transfer. The simulations show that for a given posture: RAZ orientation to the sun may account for a 1 C range in body [...]