Crocodiles are the largest living reptiles and are the closest relatives to the dinosaurs. There are twenty one species of crocodile in the world. Two of these species are in Australia – one lives in salt water, the other in fresh water.
The crocodile’s natural home is in the water. It can swim at speeds of up to fifteen kilometres per hour. The crocodile lies motionless under water for hours, with just its nostrils and eyes visible above the surface. Its dark brown or green scales blend with the colour of the water so it looks like a floating log. The crocodile can hurl itself out of the water to either grab its prey in its jaws or whip the prey into the water with a flick of its tail.
Crocodiles are found only in the tropics where they can keep an even blood temperature. To maintain their temperature, crocodiles spend their time sun baking on river banks and sand bars.
Crocodiles take good care of their young. The female digs a hole on the river bank, lays forty to fifty eggs and covers them with sand. Then she keeps watch for animals such as goannas that eat crocodile eggs. After twelve weeks, the female digs out the baby crocodiles and gently carries them to the water in her huge jaws.Thousands of Australian crocodiles have been hunted and killed over the years because their skins make good leather. Today, there are only a few thousand saltwater crocodiles left. An animal that has survived unchanged since dinosaur days is now threatened by its worst enemy- humans.