Higham, T.E.*; Davenport, M.; Mattingly, W.B.; Jayne, B.C.: Effects of turning angle on sprinting performance of three ecomorphs of arboreal lizards

Most studies on the locomotion of animals are for straight, steady speed movements; however, many species often perform maneuvering or intermittent locomotion in their natural habitats. Lizards, including several arboreal species, have been common models for testing locomotor performance. However, no previous study has determined how maneuvering on arboreal perches may affect locomotor performance of lizards. Thus, for three sympatric species of arboreal lizards (Anolis lineatopus, A. grahami, and A. valencienni) that are different ecomorphs with different sprinting abilities, we determined how the angle of turning affected locomotor performance. We used high-speed video (250 images/sec) to record the maximal running speeds of the lizards on a two-meter racetrack made of 4.8 cm diameter pipes covered with fiberglass mesh and inclined 30�. We used racetracks that were straight or had turn angles of 30� or 90� at the midpoint of the track, and we quantified the elapsed time and speeds of lizard locomotion for the middle 30-cm of the track. The total elapsed time to travel 30 cm increased significantly with increased turn angle for all three species, but the magnitude of the increase in elapsed time varied among species. Pauses in locomotion became significantly more frequent and longer as turn angle increased, and the twig anole, A. valencienni, paused more than the other two species. As turn angle increased, turning by jumping (rather than running on the perch) occurred more frequently for all species. Supported by NSF IBN 99-83003.