Temperature regulation in the smallest ungulate, the lesser mouse deer ( Tragulus javanicus)

Abstract

1. 1. The rectal temperature, oxygen consumption, respiratory frequency, and total evaporative water loss were measured in the Lesser Mouse deer ( Tragulus javanicus) at air temperatures of 10–40°C. 2. 2. The rectal temperature (mean, 38.4°C) was similar to that of other ungulates. It was relatively constant between air temperatures of 15–30°C, but the mouse deer became hyperthermic at air temperatures >30°C. 3. 3. The oxygen consumption was minimal (mean, 0.539ml O 2/g/hr.) at air temperatures between 26.6 and 29.0°C. The oxygen consumption was close to the value predicted for placental mammals, from their body wt. At lower air temperatures, the animals shivered and their oxygen consumption increased. 4. 4. Respiratory frequency increased at high air temperatures but, under the conditions of the experiments, total evaporative heat loss did not account for >54% of the metabolic heat production. 5. 5. It was concluded that the mouse deer is not particularly well adapted to heat or cold. This conclusion conforms with its behavior, habitat and distribution.