title: Gait-specific metabolic costs and preferred speeds in ring-tailed lemurs (Lemur catta), with implications for the scaling of locomotor costs.
abstract: Metabolic costs of resting and locomotion have been used to gain novel insights into the behavioral ecology and evolution of a wide range of primates; however, most previous studies have not considered gait-specific effects. Here, metabolic costs of ring-tailed lemurs (Lemur catta) walking, cantering and galloping are used to test for gait-specific effects and a potential correspondence between costs and preferred speeds. Metabolic costs, including the net cost of locomotion (COL) and net cost of transport (COT), change as a curvilinear function of walking speed and (at least provisionally) as a linear function of cantering and galloping speeds. The baseline quantity used to calculate net costs had a significant effect on the magnitude of speed-specific estimates of COL and COT, especially for walking. This is because non-locomotor metabolism constitutes a substantial fraction (41-61%, on average) of gross metabolic rate at slow speeds. The slope-based estimate of the COT was 5.26 J kg(-1) m(-1) for all gaits and speeds, while the gait-specific estimates differed between walking (0.5 m s(-1) : 6.69 J kg(-1) m(-1) ) and cantering/galloping (2.0 m s(-1) : 5.61 J kg(-1) m(-1) ). During laboratory-based overground locomotion, ring-tailed lemurs preferred to walk at ~0.5 m s(-1) and canter/gallop at ~2.0 m s(-1) , with the preferred walking speed corresponding well to the COT minima. Compared with birds and other mammals, ring-tailed lemurs are relatively economical in walking, cantering, and galloping. These results support the view that energetic optima are an important movement criterion for locomotion in ring-tailed lemurs, and other terrestrial animals.
authors.affiliation: Department of Anatomical Sciences, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA. matthew.oneill@ stonybrook.edu
authors.forename: Matthew C
authors.initials: MC
authors.lastname: O'Neill
mesh_terms: D000818:Animals; D001481:Basal Metabolism; D001696:Biomechanical Phenomena / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005684:Gait / Q000502:physiology*; D007900:Lemur; D016014:Linear Models; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D012146:Rest; D012420:Running / Q000145:classification / Q000502:physiology*; D013045:Species Specificity; D016138:Walking / Q000145:classification / Q000502:physiology*