Continuous radiotelemetric records of the deep body temperature of some unrestrained African mammals under near‐natural conditions

Abstract

The deep body temperatures of a wide range of animals have been recorded in the literature. The majority of these records has depended upon discrete measurements made while the animal was captive and restrained, or immediately after death by shooting. Estimates of the variation in deep body temperature have been achieved by making a series of measurements of rectal temperature of one animal at different times of the day, or by making a series of single measurements on several animals immediately upon captivity or sudden death at different times of the day. Until recently it has been impracticable to make continuous measurements of the deep body temperature of unrestrained mammals in a natural or nearnatural environment and virtually no such records existed when this study was undertaken. In consequence, there was no reliable information concerning the temporal pattern of the deep body temperature of a range of mammals under these circumstances, and it was not possible to determine the range of nychthemeral (24 hourly) variations in deep body temperature that occur among the mammalian species generally described as being homoeothermic. The development of miniature recorder systems and radiotelemetric systems for monitoring physiological parameters of unrestrained animals now makes the collection of such data technically feasible. A batteryoperated system of radiotelemetric thermometry designed for this purpose (Bligh & Robinson, 1963; Robinson, 1964) has been used to make a series of continuous 24-48 hr records of the deep body temperatures of several mammalian species in East Africa. These animals were confined in a paddock area, but were otherwise unrestrained at a location where they occur, or have occurred, naturally or where they are customarily husbanded.