Bite Performance of Captive Alligator Snapping Turtles (Macrochelys temminckii) Improves after Reintroduction

Abstract.— Alligator Snapping Turtles (Macrochelys temminckii) possess unique head morphology that suggests strong natural selection for bite performance, which likely influences foraging and prey selection, as well as the outcomes of intrasexual aggressive encounters, mating, and defense against predators. Therefore, bite performance has the potential to directly and indirectly impact fitness. In this study, we assessed the effects of captivity on bite force by comparing the performance of captive and reintroduced M. temminckii. On average, free-ranging M. temminckii bite with greater force than do individuals residing in captivity, and captive individuals housed under seminatural conditions in outdoor ponds outperformed those housed indoors. Further, we found that free-ranging M. temminckii released into different river systems performed comparably and required less provocation than captives to display gaping and biting behavior. It remains to be determined whether the observed performance differences were more strongly influenced by physiological limitations on muscle performance or by behavioral variation in motivation to bite with maximum force.