SREL Reprint #2149

Behavior of hatchling Alligator mississippiensis exposed to ice

John R. Lee, Vincent J. Burke, and J. Whitfield Gibbons

Introduction: The range of the American alligator (Alligator mississippiensis) is largely confined to areas where bodies of water do not freeze for extended periods of time. For this reason, cold temperature tolerance of alligators has been the subject of few studies (Chabreck, 1965; Brisbin et al., 1982; Brandt and Mazzotti, 1990). Hagan et al. (1983) reported that adults would submerge with only the tips of their snouts above the water, around which ice formed as the surface of the water froze. They referred to this behavior as the "icing" response. Brandt and Mazzotti (1990) reported on the responses of nine small (28-56 cm) alligators to the partial freezing of an artificial pond in South Carolina. The pond contained no adults. Five of the larger animals had their nostrils above the ice (i.e., icing), whereas the remaining four were trapped under the ice for at least 12 h. The two smallest animals, hatchlings (< 50 cm TL), were among the trapped individuals and were the only two animals that did not survive the forced submergence. Brandt and Mazzotti (1990) bypothesized that hatchlings are incapable of surviving even short periods of ice formation. They suggested that their inability to maintain air holes during ice formation and physiological intolerance to low temperature may limit the northern distribution of the species. They speculated that juveniles may survive severe cold fronts by overwintering in dens with adults, as suggested by McIlhenny (1935) or through the use of air holes maintained by the adults. Here we report the behavior of nine hatchling alligators (< 40 cm TL) inhabiting an artificial pond with two adults during a period of freezing weather in South Carolina.

SREL Reprint #2149

Lee, J.R., V.J. Burke, and J.W. Gibbons. 1997. Behavior of hatchling Alligator mississippiensis exposed to ice. Copeia 1:224-226.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).