Locomotory energetics in a marsupial, Setonix Brachyurus

Abstract

The gait patterns, rates of oxygen consumption, body temperature and sweat gland activity were examined in S. brachyurus during locomotion on a treadmill. At speeds up to 12.6 km h-1 the animal moved in a quadrupedal bound occasionally punctuated by six or seven hops. At the higher speeds within this range, stride frequency became relatively constant and increases in stride length were the primary determinants of increased speed. Rates of oxygen consumption increased linearly with speed of locomotion up to 7.6 km h-1; above this range the animals would not run for prolonged periods when wearing a gas collection mask. The gradient of this line was similar to that predicted for a eutherian of similar body mass, but the extrapolation to zero speed was much higher than found in other mammals. As the quokka increased speed, a greater proportion of the heat produced while running was stored. At 7.6 km h-1, this was 60% of the total production. Active sweat glands were demonstrated on the limbs and feet during locomotion.