Optimal Foraging by Patch and Prey Selection in Thamnophis Sirtalis Similis

Abstract

Patch and prey selections by blue-striped garter snakes (Thamnophis sirtalis similis) were examined in a series of simultaneous choice situations. We presented snakes with choices between small or large patches (defined by the size of the bowl in which they foraged) containing either small or large prey fish and recorded subject choices, attacks made, and capture success. T. s. similis appeared to optimize energy investments by discriminating between differing patch and prey characteristics and choosing those situations characterized by the lowest procurement cost. Subjects foraged successfully most often in small patches with large prey, where they also made the fewest mean attacks per fish captured. Choices followed success rates in that T. s. similis selected small patches with large prey most often. Results are discussed in light of foraging optimization in other garter snakes and ectotherms in general.