ABSTRACT

Thermoregulation, or the ability to regulate body temperature within acceptable limits, is a major factor in ungulate ecology. Traditionally and most frequently, thermoregulation has been studied using the Scholander approach of delineating the limits of the thermoneutral zone. Progress in understanding ungulate thermoregulation and applying field observations to answer management questions depends on detailed mathematical analyses of variables affecting heat flow between the animal and its environment. In most wild ungulates, core temperatures range between 36 and 40°C with no apparent relationship to body weight. Skin temperatures of ungulates exposed to solar radiation average up to 6.4°C higher than those in the shade while moderate windspeeds reduce skin temperatures by up to 8.5°C from still conditions. Nontraditional temperature-metabolism relationships have also been recorded in wild ungulates. To minimize thermoregulatory costs and maintain thermal equilibrium, an animal must adjust its thermal resistance to heat transfer as operative temperature changes.