The crocodiles, alligators and caimans and the single species of gavial are the 3 families which together make up this order. All are powerful amphibious carnivores, preying on a range of vertebrate animals, although juvenile crocodiles also eat insects and other small invertebrates. Crocodilia are the most direct evolutionary descendants of the archosaurs, the dominant animal life forms from 190 to 65 million years ago. There are about 21 species alive today - 13 in the crocodile family,
7 alligators and caimans, and 1 gavial. All inhabit tropical and subtropical regions. Males and females look alike in all species, though males tend to grow larger than females.
All members of the order have elongate short-limbed bodies, covered with horny skin scales. Thickened bony plates on the back give added protection. The crocodilians have long snouts with many conical teeth anchored in deep sockets in the jaw bones. Breathing organs are highly modified for underwater predation - the external nostrils, on a projection at the snout-tip, have valves to close them off. A pair of flaps in the throat forms another valve which enables the animal to hold prey in its open jaws beneath the surface, without inhaling water.
Both crocodiles and alligators possess a pair of large teeth near the front of the lower jaw for grasping prey. In the crocodiles, these teeth fit into notches in the upper jaw and are visible when the jaws are closed, while in the alligators, the large teeth are accommodated in bony pits in the upper jaw.
West African Dwarf Crocodile
Range: W. Africa, south of the Sahara.
Habitat: Streams and lakes.
Size: 5 ft (1.5 m).
Also known as the short-nosed crocodile, this animal is indeed characterized by its unusually short snout. It is now extremely rare owing to over exploitation for skins and to the destruction of its habitat. It resembles the New World alligators in appearance and size, although it is a member of the crocodile family. Little is known of its biology and breeding habits.
Morelet's crocodile, also called the Mexican or soft-belly crocodile, lives on the eastern coastal plane of Mexico, ranging south along the Caribbean coast through Belize and also into Guatemala. It inhabits slow-flowing water in swamps and marshy areas, and sometimes in rivers that flow through forests. By day it basks in the sun, or lies submerged with just its eyes, ears and nostrils above the water. Hunting takes place mainly at night. The diet changes with age. Young eat invertebrates, such as insect larvae and small fish, while juveniles feed on snails and small water mammals. Adults can tackle a range of prey, from turtles and lizards to small domestic animals, even dogs.
This rare North American crocodile has a blunt, alligator-like snout. Morelet's crocodile is similar to the American, but its skin is darker in colour.
At the end of the dry season, the female builds a nest of vegetation up to 3m (10 ft) across and lm (3.25 ft) high close to water, occasionally on floating debris in the water itself. She remains nearby until the eggs hatch about 80 days later, and helps the youngsters out of the nest. Males sometimes assist with the early care of hatchlings. In hard times, hatchlings may be cannibalized.
Distribution: Mexico, Belize.
Habitat: Freshwater swamps and rivers in forests.
Food: Lizards, turtles, fish and birds.
Size: 1.8 - 2.5 m (5.9 - 8.2 ft).
Maturity: 9 years.
Breeding: 18 - 48 eggs laid in nest at end of dry season.
Life span: 65 years.
Size: 4 - 7 m (13.25 - 23 ft).
These crocodiles live in the middle and lower reaches of the Orinoco River, Venezuela, where they prey on fish, birds and land animals. Females lay their eggs in holes dug into sandbars during low-water periods in January and February. The eggs hatch when the rains arrive about 70 days later. A mother will guard her young for up to three years.