Thermoregulatory Behaviors The American alligator exhibits different adaptive behaviors to thermoregulate and maintain body temperatures within a preferred temperature range, which has been experimentally determined to be between 29 and 31°C (Huey, 1974; Asa et al., 1998). Alligators are capable of maintaining an internal body temperature that is markedly different from the ambient temperature of the environment in which they live by selectively moving through different temperature zones (a process called microhabitat selection) and by assuming different body postures (Figure 1). Alligators have adapted many thermoregulatory behaviors to do so, most notably of which is their shuttling between water and land (Asa et al., 1998; Brandt and Mazzotti, 1990). The thermal stability of water makes it the most essential component to the alligator’s habitat, as it is used to mediate alligator body temperature in the midst of environmental temperature fluctuations (Fish and Cosgrove, 1987; Asa et al., 1998; Spotila et al., 1972). Alligators remain in the water on very cold days to maintain a body temperature above ambient temperature, but may also bask in the sun to warm up if there is adequate sunlight (Asa et al., 1998; Brandt and Mazzotti, 1990). However, basking primarily occurs in the spring and fall (Smith, 1979).
Alligators employ a similar strategy in response to freezing water. To survive freezing conditions, alligators exhibit a submerged posture (Figure 2) in which they extend their body into deeper and warmer waters while they keep their snout above the water surface (Brandt and Mazzotti, 1990; Smith, 1979). It has been reported that this behavioral adaptation has enabled some alligators to survive ambient temperatures as low as 0.4°C (Brandt and Mazzotti, 1990). Moreover, alligators often assume different positions on the water’s surface to control body temperature by exposing more or less of their dorsal surface (Fish and Cosgrove, 1987; Smith, 1979). Greater exposition of their dorsal surface will cause the alligator to heat up faster, as a larger surface area leads to the absorption of more solar radiation (Smith, 1979).
American alligators have also been observed to brumate in dens (Brandt and Mazzotti, 1990; Smith, 1979). Overwintering is another thermoregulatory behavior that enables the alligator to withstand freezing environmental temperatures (Smith, 1979). The alligator’s use of different postural positions, their microhabitat selection between land and water, and their retreat into dens are three behavioral adaptations by which the American alligator thermoregulates.
Niche and Ecological Implications
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