Telemetering in Thermobiology: A Study of Mammalian Hair

Abstract

An evaluation of the effectiveness of hair as insulation in a cold environment was performed using radio telemetry. Two adult male rats, telemetered for deep body temperature, were placed in an 18°C environment. After five days of monitoring temperature, food intake and body weight, each animal was shaved of all hair and observed an additional five days. Following shaving, both rats increased food intake, lost weight and showed lowered mean daily body temperatures, though in only one was the latter significantly lower. The increased metabolism after shaving was estimated to be between 25.2% and 51.1% greater than the preshave value in one animal, and between 23.4% and 32.9% in the other. The lowest increases were recorded in the rat tolerating the lower mean temperature. On the basis of food intake alone, metabolic demands of the shaven rats at 18°C were shown to be equal that of normal rats at 12°C. The advantages of using telemetry and continuous monitoring of temperature is discussed with regard to the results of this experiment.