Limb Use During Burial of the Sandfish Lizard

Meeting Abstract

97.1  Sunday, Jan. 6  Limb Use During Burial of the Sandfish Lizard SHARPE, S.S.*; MASSE, A.; TAZ, H.; GOLDMAN, D.I.; Georgia Tech; Georgia Tech; Wesleyan College; Georgia Tech

Desert dwelling animals like the sandfish lizard (Scincus scincus) dive into sand to escape heat and predators. The sandfish swims subsurface using a traveling wave along its body with little movement of the limbs. However, above surface, limbs are used during initial burial into the substrate and burial occurs in approximately 1.5 body undulations (< 1 s). To investigate the role of limbs during burial, we track limb movements during burial in 0.3 mm diameter glass particles using high-speed visible-light video and x-ray imaging. Sandfish (N = 3 animals, mass = 16.2 ± 1.4 g) use a stereotyped limb pattern and body undulation during burial. During the first undulation cycle the forelimbs are pressed against the body sequentially just before each side of the body becomes convex and stay there for the remainder of swimming. Hindlimbs adduct sequentially during the first undulation cycle, just after forelimb adduction and when the body is maximally convex. We hypothesize that since the hindlimbs are the last to adduct, these limbs are important for burial. To test this, we examine burial performance while restraining limbs using adhesive tape. Each animal was given 10 minutes to bury subsurface with limb restraints, and trials were accepted when animals attempted to bury. Animals readily buried when hindlimbs were bound but took a larger number of undulations (4 ± 2, P < 0.01) to bury than unbound animals. When forelimbs were bound, animals buried in 7 of 15 trials (N = 5 animals, n = 3 trials each), and all trials except one took over 4 undulations. When all limbs were bound, burial occurred in only 1 of 15 trials. These results imply that appropriately timed limb-ground interactions are critical to facilitate rapid burial.

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