Some alligators do build nests. It really just depends upon the species, the environment in which they reside, and what they prefer. Some alligators build nests while others prefer to just lay their eggs on land nearby the water near tall, soft grass for protection and easier access to food.
Mating season for alligators occurs from mid April through May. To attract females, males display behaviors such as slapping their heads on the water and producing a deep rumbling bellow. Once a male and female pair up, they will swim together, touch each other’s snouts, and blow bubbles. Mating takes place in the water and when it is completed the male disperses and the female is then left to search for a place to build a nest to lay her eggs.
Female alligators construct a nest by mounding up vegetation such as leaves, sticks, and mud in a sheltered spot in or near water. During this process females construct these nests by using their entire bodies and tail to clear an area. They use their jaws to gather and drag vegetation, and their hind legs are used to dig the hold in the mound for the eggs. After completing the nest, the female alligator can be found depositing all of her eggs (usually ranges anywhere from 20 to 50 eggs) at once and covers them up with more vegetation for incubation.
The female may move vegetation around in order to keep the eggs at a fairly constant temperature. The female alligators stay near the nest during the incubation period and actively defend it from predators. Raccoons are a common predator when it comes to alligator eggs. Females may be aggressive towards humans that come near the nest. They may be seen display behaviors such as hissing and charging intruders, it is for this reason that alligator nests should best be avoided and not approached for any reason.
An alligator’s eggs usually incubate for about 65 days. During this time, the alligator embryos develop and the sex is determined by the temperature at which the eggs were incubated. This is known as temperature dependent sex determination. A temperature of 30 degrees Celsius (86 degrees Fahrenheit) or below produces females and a temperature of 33 degrees Celsius (91.4 degrees Fahrenheit) or higher produces males. In between those temperatures at 32 degrees Celsius) 89.6 degrees Fahrenheit) there is usually a 50/50 chance of getting males or females.
Once incubation is complete and the hatchlings are ready to emerge from their eggs, they emit a “yerping” sound. A few hatchlings yerping stimulates the other hatchlings in the clutch to yerp as well. This then signals the female that the eggs are about to hatch so she carefully opens the nest. The hatchlings can then be found tearing through the leathery eggs with an egg tooth that they are equipped with. This egg tooth is located on the tip of their snout and will fall off after the alligator is a few days old. The mother alligator can also help the hatchlings emerge from their eggs by rolling the eggs between her tongue and palate. This helps to ensure that all of the eggs hatch at the same time. Hatchlings typically emerge from their eggs and then stay near the nesting site for a couple of years.