Reproductive Biology of Alligator Snapping Turtles: Behavior, Reproductive Investment, and Nest Predation

Successful production of offspring (and ultimately grand-offspring) defines organisms\u27 fitness. Therefore, I investigated three critical aspects of reproduction in the alligator snapping turtle (Macrochelys temminckii), a model organism that is of great conservation interest. Specifically, I studied: (1) nesting behavior and (2) maternal reproductive investment patterns in a captive alligator snapping turtle population housed outdoors under semi-natural conditions, and (3) nest predation patterns in a reintroduced population. Both sites were located in the species\u27 geographic range in southern Oklahoma. Females averaged 25 terrestrial forays prior to successfully nesting and average nesting duration was 185 minutes. Nesting activity positively correlated with increasing temperature, but did not correspond with rainfall. Larger females tended to lay larger eggs but the number of eggs per clutch was not related to female size. Instead, females primarily increased fecundity by allocating extra resources to producing more eggs rather than larger eggs. Raccoons (Procyon lotor) are the most important nest predator in the population studied, and I investigated the role of soil disturbance and turtle olfactory stimuli in raccoon responses to artificially constructed alligator snapping turtle nests. Raccoons primarily used soil disturbance cues to detect artificial nests; however, after being detected nests with soil disturbance were more likely to survive an encounter with a raccoon than a nest that lacked visual stimuli. The conspicuous nesting strategy employed by M. temminckii is discussed as a potential evolutionarily adaptive strategy to disguise the exact location of the clutch from predators