Diet, Body Size and the Energy Costs of Locomotion in Saltatory Primates

We report the energetic costs of locomotion in five nocturnal, saltatory prosimians. Using data on nightly travel distance, locomotor frequencies, distance and height change in each locomotor mode, we calculated absolute and relative costs of locomotion. Locomotion contributes at most 2% to total daily metabolic energy costs, consistent with most estimates for quadrupedal species. Tarsius, the smallest, has the lowest absolute and relative cost of locomotion, but the third smallest, Avahi, has the highest absolute and relative costs of locomotion, followed by the largest species, Otolemur crassicaudatus, which incurs particularly high costs in upwards-directed locomotion. Lepilemur’s costs of locomotion are maintained at an unexpectedly low level by remarkably short nightly travel distances.