Meeting Abstract
Tail autotomy is an escape strategy commonly observed in lizards that involves the voluntary shedding of the tail in response to a predatory stimulus. In leopard geckos (Eublepharis macularius), the tail accounts for one-third of the body length and one-fourth of the animal’s mass. Recent data suggests that rapidly losing this large caudal mass results in an anterior shift of the center of mass and consequent kinematic adjustments during steady locomotion. However, in addition to a loss of mass, autotomy may also result in the loss of a hypothesized locomotor function of the tail. Lateral undulations of the tail are suggested to contribute to balance and stability. Therefore, we hypothesize that restricting tail movement while walking will have similar effects to autotomy on body and limb kinematics. In contrast, if tail undulations do not contribute to locomotion, body and limb kinematics should remain unchanged after restricting the tail. Leopard geckos (n=10) were filmed walking on a level surface under three conditions: (1) original tail intact, (2) restricted tail, and (3) autotomized tail. Tails were immobilized by attaching a stiff graphite rod (< 1 g) along the length of the tail. 3D kinematics of the body, fore- and hindlimbs were assessed in 3-5 strides per individual per treatment. Restricting the tail resulted in a greater angle of rotation and rotational velocity of the pelvic girdle as the gecko attempted to compensate for not being able to undulate the tail. Additionally, an immobilized tail resulted in decreased femur depression and knee angles, similar to the response to autotomy. These results suggest that tail undulations play a role in maintaining stability during locomotion, a role that is lost after autotomy. Supported by NSF IOS-1147043 and the UCR Newell Fund.
