Crocodilians are aquatic, predatory reptiles with long jaws and bony plates of armour on their bodies. The family includes crocodiles, alligators, gharials and caimans. Most live in tropical rivers and lakes. The largest species are the Nile crocodile and the saltwater crocodile, both of which grow up to 7 metres (23 feet) long. They can easily bring down large prey such as antelope, which they ambush at the water’s edge, dragging them underwater to drown. Crocodiles are expert swimmers, but can also run at speed on land.

Hunting

Crocodiles feed on a wide range of prey, including fish, turtles, birds and mammals. Having eyes and nostrils on top of their heads allows them to lie in the water with their bodies almost completely hidden.

They also have transparent “third eyelids” which closes to protect their eyes when they submerge. They can close off part of their throats to avoid swallowing water while feeding.
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Caring for their young

Like most reptiles, crocodiles lay eggs on land. Females lay from 15 to 80 eggs in a pit they dig not far from the water’s edge. Smooth and white with hard shells, eggs are about the same size as hens’ eggs. The mother carefully covers them up with sand to keep them warm and dry.

Female crocodiles guard their eggs from predators. Unguarded eggs might be eaten by mongooses, snakes or lizards, or could rot if exposed to wet weather. At the first sign of rain, the mother positions her body over the eggs to protect them from the downpour.

After three months, the young crocodiles finally hatch. When they are ready to hatch, the babies start squeaking loudly. This signals to the mother to dig them out of the nest.
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The hatchlings stay with their mother for three months, after which they go off to to establish territories of their own. The young may then be preyed on by herons, storks, eagles and other predators. Only one or two will live to adulthood. Young crocodiles feed on small prey, including crabs or frogs. Older ones feed on fish or animals that are already dead.

Alligators

Alligators are related to crocodiles, but their snouts have a more rounded shape. They also lurk in tropical rivers and swamps and feed on animals that come down to the water’s edge to drink. Their eyes, ears and nostrils are on the tops of their heads so that they can lie in wait almost completely under the water. Alligators can grow up to 4.8 metres (15.7 feet) long.

Gharials

Gharials, also known as gavials, are related to crocodiles and alligators. They have long, narrow snouts, lined with needle-like teeth. They live in rivers and mangroves of Southeast Asia, feeding only on fish. Gharials can reach lengths of up to 7 metres (23 feet) long and are very agile swimmers.