The American Crocodile
by Rebecca
Ancestors of Crocodiles
Crocodiles are very interesting. The earliest crocodiles lived with the dinosaurs. The earliest known crocodile ancestor was called a protosuchian. The protosuchian lived about 200 million years ago. It was about three feet long with sharp teeth and covered with bony spines. After the protosuchian came the stenosaurus, which lived about 180 million years ago. Still yet came another ancestor of the crocodile, the deinosuchus, was the first United States ancestor of the crocodile. The deinosuchus was up to fifty feet in length and had a skull about six feet long.Its name meant "terrible crocodile" in Greek, and this crocodile did live up to its name.
Characteristics of Crocodiles
Crocodiles are now a bit different, but they have not changed much. They have backbones and lungs. They must come to the surface to breathe. A crocodile can stay underwater for three to five minutes. Crocodiles have four-chambered hearts. They are cold-blooded and have no lips. Their mouths can't close tight. The color of their skin is dark gray or green. Crocodiles have a valve that closes their air pipe so that water can't enter the lungs while they are underwater. The crocodile is usually thirteen to eighteen feet long. They have bony plates on their backs. Their bodies are cigar-shaped and have tough hides. A crocodile can live fifty years. Crocodiles weigh, on average, 1350 pounds. They have powerful legs and huge tails. Their feet are partially webbed and have long nails. Crocodiles use their tails to capture food. They have thirty to forty teeth, which interlock when its mouth is closed. A crocodile has a good sense of hearing and smelling.
Differences Between Crocodiles and Alligators
Crocodiles and alligators are different. Alligators have more teeth than crocodiles. The main difference is that crocodiles have pointed snouts, while alligators have flat snouts. Another difference is that crocodiles are more agile than alligators.
Eating Habits
A crocodile's jaws can crush the bones of a small animal when the jaws are being closed. They eat fish, turtles, and water birds, but usually anything they can catch - including people! A crocodile always swallows his food whole.
Habitats
Crocodiles live in the Everglades. They prefer large shallow bodies of freshwater or saltwater. Also, they live in the warmest, most tropical region on earth. In the extreme heat or cold, they go into hibernation and estivation. When doing this, they bury themselves in mud and live off stored fat.
Eggs and Babies
Female crocodiles make great mothers. The females are the ones that make the nests out of sand, mud, and weeds. Nests are built on the water's edge and are really just shallow holes. These nests are only a few inches high. There are about twenty to ninety eggs in a nest, but most never hatch due to predators who eat the eggs. A crocodile egg is about the size of a goose egg. When the mother crocodile hears the grunts of her babies, she helps her children push out of the nest. The babies themselves get out of the eggs using their egg tooth. When born, a baby crocodile is about eight inches long. They are born a light greenish, gray color with black crossband. Baby crocodiles eat water insects and shellfish. In some parts of the world, crocodile eggs are used for food.
Copyright ©1998 by Rebecca
All Rights Reserved