The Effect of Substrate Particle Size on Sprint Performance in Three Species of Desert Lizards

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Correlates of locomotor performance have been documented in a variety of animals including several lizard species. Sprint sensitivity, or the variation in sprint performance due to differences in habitat or substrate use, has been well studied in arboreal lizards, particularly in Anolis lizards. However, variation in locomotor performance of ground dwelling lizards on different substrates has received less attention. Here, sprint sensitivity was used to compare the sprinting abilities of lizards on three substrate types that they naturally encounter during activity. This study quantified maximum velocity in Crotaphytus bicinctores, Gambelia wislizenii, and Aspidoscelis tigris as they accelerated from a standstill and ran down a five meter runway constructed in the field. Each runway contained a different substrate. One runway contained sand particles ranging from 0.5 – 2.0 mm diameter. The second runway contained pebbles ranging 4 – 10 mm diameter and the third runway contained cobbles and boulders ranging 200 – 500 mm diameter. Each animal was run three times on each of the three substrate types. All runs were videotaped and reviewed to estimate maximal velocity. Preliminary results suggest high individual variation, but Crotaphytus bicinctores, a rock and cliff-dwelling lizard, exhibits the lowest degree of loss of maximal speed when running on different substrates, followed by Gambelia wislizenii and then by Aspidoscelis tigris. These differences will be explored in terms of morphological and ecological differences among the species.


Society for Integrative and Comparative Biology Annual Meeting (SICB)


Salt Lake City, UT