Effects of behaviour and ontogeny on the locomotor performance of a West Indian lizard, Anolis lineatopus

1. The speeds of locomotion in nature were quantified for juveniles and adult females of the lizard Anolis lineatopus during escape from a threat, feeding and undisturbed locomotion (juveniles only), and compared these data both with data gathered previously on maximal laboratory performance, and with field data gathered previously for adult males. 2. The following questions were addressed: (1) Within a particular intraspecific class, do lizards move at different speeds during different behaviours? (2) Within a particular behaviour, do intraspecific classes differ in speed? (3) Do juveniles differ from adult males in the entire distribution of speeds and distances moved when undisturbed? 3. Locomotion was typically fastest during escape, followed by feeding and then undisturbed locomotion. Within escape and undisturbed activity, the intraspecific classes differed significantly in absolute speed, relative speed and percentage maximal speed. For the entire distribution of movements during undisturbed locomotion, juveniles moved shorter distances and at slower speeds (between 0 and 10% of maximal) than adult males. 4. The relatively high percentages of maximal speed that juveniles employ when escaping and feeding provide limited support for the hypothesis that juveniles are compensating for their relatively poor sprinting capacities.