Alligators are absolutely amazing animals. They have been around for millions of years and are about as close as humans will ever get to seeing a living dinosaur. Alligators are large reptiles, members of the order Crocodylia. Alligators and crocodiles are, therefore, closely related, and people often confuse one with the other; however, these two reptiles are very different.

An alligator is distinguished by its wide, rounded snout and black color. Also, all of its upper teeth can still be seen when its mouth is closed. Crocodiles, on the other hand, have narrow, pointed snouts, a grey-green color and only the fourth tooth on the lower jaw can be seen when the animal's mouth is closed,

https://animals.howstuffworks.com/reptiles/alligator.htm

Alligators can be quite dangerous. They are instinctual living machines. An alligator's brain weighs only 8 or 9 grams and would take up only one-half of a tablespoon.

This lack of brain power means there is no such thing as a "nice alligator". If it's hungry, an alligator will eat anything that moves. Pets and children who wander near an alligator pond are frequent victims of this instinctive behavior.

Your basic alligator has a large head, a lizard-like body, four stubby legs and a long tail.

Alligators are reptiles, and they are members of the Crocodylia order. In this order are 23 different species, including the American alligator, Caimans and a variety of crocodiles.

The basic Crocodylia body form has been around for over 180 million years, making alligators and crocodiles living dinosaurs. All of these animals have the same basic layout: big heads, long, lizard-like bodies, four stubby legs and long tails.

Male alligators are, on average, about 11 feet (3.5 meters) long and 600 pounds (270 kg). Females are, on average, about 8 feet long and weigh about half as much as male alligators. Males can actually get much larger -- 1,000 pounds is not unusual. At the Alligator Adventures alligator park in Myrtle Beach, SC, a very large crocodile named Utan weighs in at 2,000 pounds and is almost 20 feet long. He is claimed to be the largest living Crocodylian in captivity.

Breeding

Alligators breed in the spring. The female then builds a nest of mud and vegetation that is about three feet (1 meter) high and 6 feet (2 meters) in diameter. She lays 30 to 50 eggs and buries them in the rotting vegetation. The eggs are white, hard and slightly bigger than a large chicken egg.

The nest provides heat -- it is like a big compost pile and heats up naturally because of the decomposing vegetation. The alligator eggs respond to the temperature. If the temperature is in the low 80s F, the hatchlings will be female. If the temperature is in the low 90s F, they are male. For temperatures in between, the resulting hatchlings are mixture of males and females.

Classification/Taxonomy

The taxonomy of alligators, according to the Integrated Taxonomic Information System (ITIS), is:

Kingdom : Animalia
Subkingdom : Bilateria
Infrakingdom: Deuterostomia
Phylum : Chordata
Subphylum: Vertebrata
Infraphylum : Gnathostomata
Superclass: Tetrapoda
Class: Reptilia
Order : Crocodilia
Family: Alligatoridae
Genus: Alligator
Species : Alligator mississippiensis (American alligator, Florida alligator, Mississippi alligator, Louisiana alligator),
Alligator sinensis (Chinese alligator)