IRSCHICK, D.J.*; JAYNE, B.C.: A comparative field study of the arboreal locomotion of lizards

Few studies have rigorously quantified the habitat and movements of arboreal animals, particularly in a comparative context. We quantified the available habitat, habitat use and movement patterns of three morphologically different arboreal Anolis lizard species at a field site in Jamaica (A. lineatopus, A. grahami and A. valencienni). We focused primarily on how the incline and diameter of perches affected the preferred speed of locomotion. The habitat was dominated by narrow perches (70% of perches were less than 1 cm diameter) and steep inclines (44% of the inclines were greater than 70 degrees). All species used steep inclines at similar proportions as available in the habitat, but they also used shallow inclines (<25 degrees) at greater frequencies than available in the habitat. One species (A. valencienni) primarily used narrow perches, whereas the other two species primarily used broad surfaces, despite the paucity of such perches in the habitat. The majority of movements were short in distance (<15 cm), and relatively slow. For example, for A. grahami, 90% of the speeds were less than 40% of maximum capacity. Two species (A. valencienni and A. grahami) tended to move on steep uphill surfaces more often than on steep downhill surfaces, but A. lineatopus exhibited the opposite trend. Multiple regression analyses revealed that average speed per movement was significantly affected by the distance per movement, incline, perch diameter and perch height. Lizards moved more slowly when they were on steep uphill compared to steep downhill perches, and also when they were on broad compared to narrow perches. This work was supported by the National Science Foundation (IBN 9983003)