The Effects of Caudal Autotomy on the Kinematics of Anolis carolinensis Running on an Arboreal-Like Substrate
Date
2014-06-02
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Caudal autotomy is a well-researched predation-escape mechanism used by Anolis lizards. This ‘self-sacrifice’ involves a neuromuscular event in which the tail is severed along an intravertebral fracture plane proximal to the point of a predator’s grip. The phenomenon of autotomy has persisted in anoles for millions of years due to its benefit of increasing the probability of survival. However, autotomy also incurs in the lizard a metabolic deficit, behavioral modifications, and locomotor consequences. Past research has documented post-autotomy changes in sprint speed, step length, and time spent pausing. I hypothesize that these gross locomotor effects can be explained by changes in limb kinematics. Using high-speed video cameras and MATLAB I recorded and compared the characteristic motions of the front and hind legs pre- and post-autotomy in running Anolis carolinensis (N=4), a trunk-crown anole with morphology representative of a broad range of anole ecomorphs. Post-autotomy, the lizards showed significant increases in average velocity, forelimb step frequency, and hindlimb step frequency (p=0.025; p=0.02; p=0.035). Kinematic variables of the limb did not significantly change after tail loss, so the gross locomotor changes observed are better explained as behavioral than biomechanical.
Description
Keywords
biomechanics, anole, locomotion, caudal autotomy