ROBERTS, L. F.*; O’REILLY, J. C.; WASSERSUG, R. J.; Dalhousie University, NS; University of Miami, FL; Dalhousie University, NS: The Behavioral Responses of Serpentine and Fossorial Amphibians and Reptiles to Microgravity in Parabolic Flight

Although few vertebrate species have been observed in microgravity, certain behaviors are common. Most tetrapods interpret weightlessness as if they are upside down and therefore exhibit repetitive righting responses. However, some unusual behaviors have been observed among amphibians and reptiles in the past, including an aggressive display of a snake towards its own body, immobility in a caecilian, and skydiving postures in certain tree frogs. We exposed 53 animals from 23 different species of amphibians and reptiles to microgravity on an aircraft that flew a parabolic path. The animals were exposed to four parabolas each with twenty seconds of microgravity (<.01G) to better characterize behavioral reactions to abrupt exposure to micro-G. Highly fossorial limbless caecilians and amphisbaenians showed relatively limited movement in microgravity. Limbed quadrepidal reptiles that were non-arboreal (e.g. Leiocephalus personatus, Leiocephalus shreibersi, and Scincella lateralis) showed the typical righting response in enormous amounts of body motion and tail rotation. We interpreted the limb movements as futile attempts to grasp the substrate and the tail rotations as characteristic of righting responses. In contrast, both arboreal and non-arboreal geckos (e.g. Uroplatus henkeli and Palmatogecko rangei) showed skydiving postures like arboreal frogs. As a result of our survey more genera of amphibians and reptiles have been videotaped in microgravity than any other vertebrate class. The patterns of behavior seen in these organisms in microgravity can be understood in light of both their normal ecology and taxonomic relationships.