Breeding season begins in the spring. Although alligators have no vocal cords, males bellow loudly to attract mates and warn off other males during this time by sucking air into their lungs and blowing it out in intermittent, deep-toned roars.

The female builds a nest of vegetation, sticks, leaves, and mud in a sheltered spot in or near the water. After she lays 20 to 50 white, goose-egg sized eggs, she covers them under more vegetation, which, like mulch, heats as it decays, helping to keep the eggs warm. She remains near the nest throughout the 65-day incubation period, protecting the nest from intruders.

When the young begin to hatch, they emit a high-pitched croaking noise, and the female quickly digs them out. The young, tiny replicas of adult alligators with a series of yellow bands around their bodies, then find their way to water. For several days they continue to live on yolk masses within their bellies.

Alligators reach breeding maturity between the ages of 8 and 13 years, at which time they are about 6 to 7 feet long. From then on, growth continues at a slower rate. Old males may grow to be 14 feet long and weigh up to 1,000 pounds during a lifespan of 30 years or more.

https://www.fws.gov/endangered/esa-library/pdf/alligator.pdf