Alligators, caimans, crocodiles, and gharial together are known as “crocodilians.” That is sometimes shortened to “crocs” and still refers to all the species as a group. Crocodilians are large, meat-eating reptiles that spend a lot of their lives in the water. They mostly live in fresh to brackish water, in swamps, marshes, canals, and lakes. Alligators swim very well, mainly using their tails to propel themselves through the water, and also using their webbed feet. Their bodies are covered with scales, like other reptiles.
Alligators vs. Crcodiles
Shape of the jaw: Alligators tend to have wide, U-shaped, rounded snouts, while crocodiles tend to have longer, more pointed, V-shaped snouts.
Teeth: The fourth tooth on the lower jaw sticks up over the upper lip on crocodiles, so you can see it when their mouths are closed. In alligators, this fourth tooth is covered up.
Habitat: Crocodiles also have special glands in their tongues that can get rid of excess salt, so they tend to live in saltwater habitats. Alligators have these glands, too, but they don't work as well as the crocodiles', so alligators prefer to live in freshwater habitats.
Coming to their senses
Crocodilians are efficient hunters, and their senses are more powerful than those of most other reptiles. You may not be able to see a croc's ears, but they have excellent hearing. They have slits on their heads that lead to a well-developed inner ear, and the slits close up when they dive to keep water out.
Crocs can even hear their young calling from inside their eggshells! They also have good eyesight above water. Their eyes are placed on top of their heads so they can see well as they cruise the water looking for prey. They can probably see some color, and they have good vision at night because their vertical pupils can open wider than our round ones to let in more light. Crocs have taste buds to taste their food, and special organs in their snouts give them a great sense of smell.
Crocs are carnivores and eat whatever they can catch in the water or along the banks. That includes fish, turtles, frogs, birds, pigs, deer, buffalo, and monkeys, depending on the size of the croc. Crocs are nocturnal and feed primarily at night. American crocodiles have about 66 teeth and alligators usally have about 80 teeth, but don't chew their food. They either tear off large pieces and swallow them or swallow the prey whole if it's small enough. That means that the croc has to juggle the food around until it's in the right position, then toss its head back so the food falls down its throat. Some croc species can eat up to half their body weight in one meal. Also, when teeth are lost they regrow.
Taking Care of the Young
Crocodilian moms take really good care of their hatchlings! Crocs are one of the few reptiles that watch out for and protect their young until they are old enough to be on their own. The cow (female croc) looks for just the right place to build a nest to lay her eggs.
Some species make a mound nest out of soil and vegetable material; others dig a hole in the sandy beach for their nest. The mama croc then settles in nearby to guard the eggs from predators that might try to dig them up and eat them. When the babies are ready to hatch, they make grunting or barking noises from inside the egg, and use a short little tooth on the end of their snouts called an “egg tooth” to start breaking out of the leathery shell. Some croc moms even help by gently biting the egg to open it up more easily.
After the young have hatched, the mom carries them to the water in her mouth (except for gharials, which have mouths that are too narrow), then guards them for most of the first year of their lives. Sometimes the hatchlings get to ride on her back, too. She will threaten or attack any predator that lurks too close, and in some species she will call the hatchlings to swim into her mouth for protection—making it look like she's swallowed them!
Where Do They Live?
Crocodilians spend most of their time in the water. They even look like they belong there, appearing like logs floating in a swamp or washed up on shore. Crocs can hold their breath underwater for more than an hour. They look lazy, but they are actually very fast on their feet. Their eyes and nostrils are located on top of their heads, enabling them to see and breathe while the rest of the body is submerged. With only their eyes and nostrils showing, they glide stealthily through the water, escaping notice by prey.
Alligators are mostly found in the southern United States and the crocodiles in Africa, India, South America, and southern United States.
Crocodiles and their relatives live mostly in the warm tropical parts of the world, although alligators range into more temperate climates in the southern United States and China.
The Nile crocodile and the bird share a mutualistic symbiotic relationship, a relationship that two animals from different species interact and benefit each other. The crocodile allows the bird to sit in its mouth, eating the food between the crocodile's teeth. The bird benefits, because it is able to eat. The crocodile benefits, as its teeth are cleaned.