An opportunistic predator, a fully-grown American alligator is capable of tackling nearly all aquatic and terrestrial prey that it encounters (5). Hatchlings start life feeding on insects and freshwater shrimp, but as they grow they graduate to larger prey, taking fish, frogs and snakes, and eventually small to large mammals (8). While the American alligator is notorious for its potential danger to humans, attacks are very rare, and are usually due to provocation, habituation due to being regularly offered food, or the mistaken identification of humans for smaller prey (5).
The American alligator typically breeds in spring, between late April and early June (8), with male alligators using a variety of behaviours to attract and court females, including deep, powerful roars, slapping the head against the water and complex body postures (5). After mating, the female lays between 25 and 60 eggs in a large, torn-up mound of vegetation and mud situated on a bank or mat of vegetation. The eggs are deposited within a depression in the top of the mound, which is then covered over with more vegetation. This nest not only protects the eggs from flooding, but also aids incubation, due to the heat produced by the rotting vegetable matter (5) (8). While in the nest, the temperature to which the eggs are exposed determines the sex of the hatchlings; hence, due to variations in temperature in different parts of the nest, a mixed-sex litter is usually produced (8). Incubation usually lasts for around 65 days, depending on temperature, after which time the female, which remains in close proximity to the nest to guard it from predators, responds to calls made by the hatchlings and digs them out. Around eight to ten offspring at a time are then carried to the water in the female’s jaws. The juveniles remain close to the mother for around a year, but occasionally up to three years. Despite the maternal protection, the young are regularly preyed upon by raccoons, large fish, birds, and by large, dominant, male American alligators (5).
The American alligator is considered to be a keystone species, which means that through its activities it plays a key part in ensuring a healthy, biodiverse ecosystem. One major contribution to this role is the construction of “alligator holes”, which are depressions dug out by the alligator using its snout and tail, which hold water, providing a refuge during dry periods (5) (6). The holes provide a vital source of water for fish, insects, crustaceans, snakes, turtles, birds, and other animals (4), which further benefits the alligator by providing a convenient source of food (6). In addition, to drought, the American alligator is also capable of surviving at sub-zero temperatures. As temperatures drop, the alligator’s metabolic rate decreases, and it ceases to forage below 20 to 23 degrees Celsius, retreating to an excavated burrow where it survives the winter using stored energy reserves. Amazingly, outside its burrow, this species is also capable of surviving freezing conditions, submerging its body, but keeping its nostrils above the water to breathe, which then become trapped in the surrounding surface ice (5).