Sprint performance of a generalist lizard running on different substrates: grip matters

Abstract

Abstract The relationships between locomotor performance and major features of environmental structure, such as incline and diameter, have been consistently identified in several vertebrate groups. The effects of variation in characteristics such as texture and structural complexity, in contrast, remain neglected, and associations between sprint speeds achieved during steady‐level locomotion and the way an animal grips the surface are particularly obscure. In the present study, we have used the habitat generalist lizard T ropidurus torquatus to test the hypothesis that animals run faster on the substrates where gripping performance is higher. We ran 18 individuals on seven different substrates (wood, thin and coarse sand, coarse gravel, rock, leaf litter and grass) and recorded their maximum speeds using high‐speed cameras. Surfaces were characterized for height variation and grip, the last given by average grip performance achieved by lizards of different sizes. Maximum sprint speeds were highest on rock and grass and lowest on thin and coarse sand, and variation in performance among substrates was explained by grip: substrates in which lizards gripped stronger are those that enhanced average maximum sprint speed. This study is the first report providing evidence for variation in maximum sprint speeds achieved by a generalist lizard running on different substrates, and demonstrates how friction resulting from the interaction of the lizard with the substrate may be critically important for sprint speed.