ABSTRACT
This chapter reviews some of the evidences which indicate amphibians and reptiles behave to regulate body temperature or water content, or at least confine fluctuations within narrower limits than environmental conditions. It discusses the effect of color on some physical responses of organisms to solar radiation, and the behavioral responses that are affected as a consequence. Thermoregulatory behavior is well documented for many species of reptiles, and one can sort through literally hundreds of papers in reviewing the phenomenon. Perhaps the most widespread thermoregulatory behavior is basking; organisms gain heat by prolonged exposure to solar radiation (heliothermic basking) or to warm substrates (thigmothermic basking). The significance of behavioral thermoregulation is further elaborated by studies of natural populations. Cost/benefit ratios may be important factors to consider in studying the evolution of thermoregulatory behavior. Since amphibians lose water freely, many of their action patterns aims at conserving body water, which the chapter considers to be hydroregulation.
