Most of our insight into the energetics of terrestrial locomotion is derived from studies of metabolic expenditure of animals running under steady-state (constant speed, long duration) conditions. Non-sustainable locomotion of high intensity but short duration, of the type seen during prey capture, territorial defense, or predation avoidance represents behavior at least as important as long duration sustained locomotion, and is a type of activity with different metabolic underpinnings. This research will examine the energetics of this type of activity. The PI will investigate four aspects of non-sustainable locomotion: 1) the effects of duration, 2) the effects of different locomotor intensities, 3) the differential responses of an endotherm vs. an ectotherm to brief exercise, and 4) the role of hormones in defining this locomotor cost. The study addresses a realm of animal activity for which we have no predictive database. The preliminary data suggest that the net cost of non-sustainable locomotion may be an order of magnitude more expensive than when animals cover the same distance at aerobically sustainable speeds. If supported by the proposed research, this finding will raise fundamental questions about the consequences of some types of animal behavior, and open a new chapter in the study of animal locomotion.
