Thermoregulation and Standard Metabolism of the Slender Mongoose (Herpestes sanguineus)

Abstract

In controlled laboratory conditions, oxygen uptake, rectal temperature, total and respiratory evaporative water loss, and respiratory frequencies in the slender mongoose (Herpestes sanguineus) were measured at ambient temperatures of 5, 10, 20, 26, 31, and 43 C. Except at 43 C the experimental runs were for more than 3 h. In other experiments, oxygen uptake, level of motor activity and intra-abdominal temperatures were recorded over 24-h duration. Within the thermal neutral zone (Ta 26–Ta 31 C), resting postabsorptive oxygen uptake was 0.76 ± 0.15 ml O2/g/h close to the value predicted for mammals of similar weight (corresponding to about 42 Kcal per day for a 500-g mongoose). Rectal temperature was 38.7 ± 0.03 C, while resting respiratory frequency remained at about 40 breaths per minute. When the animals were exposed to Ta 38 C the rectal temperature was maintained at 39.8 ± 0.02 C for prolonged periods. At Ta 43 C such a steady state could not be attained, and the rectal temperature continued to rise. Heat loss at this temperature exceeded heat production by about 16%, but the added heat gain from the environment caused the body temperature to rise. Most of the heat was lost through cutaneous evaporation, respiratory evaporation accounting for about 26% of the total heat loss by evaporative means. At low ambient temperature (5 C) the metabolic rate was double that measured at the thermal neutral zone. Shivering, piloerection, and curling up into a ball-like posture were observed. It was concluded that (1) the metabolic rate of the slender mongoose is similar to that of other mammals of similar size despite their large surface area to volume ratio and (2) both respiratory and cutaneous evaporative water loss play a role in heat dissipation. Cutaneous evaporation from active sweating is the more important. This is in contrast to the situation in other carnivores like dogs and cats.