Nile crocodile

Crocodylus niloticus

TAXONOMY

Crocodylus niloticus Laurenti, 1768, India and Egypt. OTHER COMMON NAMES

French: Croco afrique; German: Nordöstliches Nilkrokodil; Spanish: Cocodrilo del Nilo; Swahili: Mamba.

PHYSICAL CHARACTERISTICS

This is a heavyset species with prominent dorsal scales or scutes arranged in even rows. Average adult lengths are 11.5 ft (3.5 m) for males and 8 ft (2.5 m) for females. Males grow to a maximum length of 18 ft (5.5 m); females to 11.5 ft (3.5 m). Young Nile crocodiles are brown or olive with strong darker markings. In adults the markings are vague and older animals are uniformly dark brown or gray. The belly is yellowish, white, or gray.

DISTRIBUTION

South of the Sahara desert throughout much of tropical and southern Africa and Madagascar.

HABITAT

This species inhabits wetlands, rivers, and lakes, inclusive of coastal areas.

BEHAVIOR

Although a social animal, adult males square off for territory and mates during the breeding season. It is common for large groups of adults of both sexes to bask and feed in one area.

FEEDING ECOLOGY AND DIET

Young Nile crocodiles feed largely on insects and spiders with frogs, fish, snakes, and other small vertebrates. Subadults and adult crocodiles mainly eat fish, although very large adults kill and eat antelopes, warthogs, domestic animals, and occasionally humans. These crocodiles use various techniques to catch their prey, including the "hide and wait" method at water holes and river crossings, waiting underwater for fish, and following scent trails to carrion, even when far from water.

REPRODUCTIVE BIOLOGY

The nesting season across Africa occurs from August to January. The female digs a nest hole above the high water line to lay 50-80 eggs. The female stays close to the nest for the 80-90 days of incubation. When the young hatch, she digs them out of the underground nest and carries them to the water. Nests are raided by a variety of predators, namely monitor lizards, hyenas, and humans. The crèche of young stay together for a month or more under the watchful eye of the parent.

CONSERVATION STATUS

The Nile crocodile forms the basis of a successful sustainable-use program for skins and meat in several African countries. In other parts of its range, notably Central and West Africa, the crocodile is in decline and there is very little status information. It is afforded some level of local protection throughout its range, and is no longer included on the IUCN Red List. As of 2002, the Nile crocodile was on Appendix I of CITES, except for ranched animals in Botswana, Ethiopia, Kenya, Malawi, Mozambique, South Africa, Tanzania, Zambia, and Zimbabwe. Nile crocodiles are on Appendix II in Madagascar and Uganda, where there is an annual hunting quota. The estimated population in the wild is 250,000-500,000.

SIGNIFICANCE TO HUMANS

There is a long history of reverence for the Nile crocodile, dating back to the time of the pharaohs when hundreds of crocodiles were mummified along with dead kings. Today there is less reverence and more fear and intolerance toward these crocodiles, which sometimes prey on livestock and humans. ♦

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