Nile crocodile

Introduction: Crocodiles belong to the Family Crocodylidae and were the dominant ruling reptiles called the archosaurs of the Jurassic era of 190 million years ago. They have changed very little since then. Features include an efficient blood oxygenation system, courtesy of a 4-chambered heart; an extra eyelid which clears debris from the eyeball; and limb joints that allow crocodiles a 'high walk' which enables them to sprint short distances. All crocodiles are aquatic, live in tropical regions and as only 23 species remain worldwide are all endangered and protected. Only 1 species of crocodile can be found in Namibia. It is the Nile crocodile (Crocodylus niloticus).

The Nile crocodile (Crocodylus niloticus), apart from being exceptionally long and heavy has a long and very uninviting set of jaws with prominent teeth.The eyes and a set of 'valved' nostrils sit on top of the head, usually visible above water when they are drifting along nearing a potential victim. Other distinguishing features include geometrically arranged bony and keeled, horny plates. The hind feet are webbed, ideal for stepping up a gear on either land or water.

Distribution: The larger rivers, lakes and swamps, river mouths, estuaries of the Kunene River eastwards from the Atlantic Ocean to Epupa Falls and as far as Ruacana Falls. They are common along the riverbanks of the Chobe and Zambezi Rivers and into Okavango Delta and Moremi Game Reserve.

Diet: Fish, catfish, antelope, zebra, buffalo and carrion. Attacks on humans are common. Crocs will also herd fish into shallow waters. If prey is too large to swallow, then crocodiles will tear it to bits by seizing a mouthful and spinning to disorientate the victim (if it hasn't died of a heart attack by then!)

Colouring: Adults are a dark green or uniform olive to grey, with a yellow or cream belly.

Breeding: May is the beginning of the breeding season for crocs. Males develop a dominance hierarchy and in July to August an elaborate underwater courtship begins. Females select a 'honeymoon suite' of a sunny sand bank, higher than the flood-water level, which affords nearby cover and decent drainage. This site remains with the female for life (unless disturbed). Females lay between 16 to 80 hard-shelled, white eggs in a hole dug with her hind legs. Nest sites are defended against predators including other crocodiles. The sex of a crocodile depends on the egg incubation temperature, higher temperatures yield males, lower produce females.

Size: Total length 2.5 to 3.5m. Max length 5.9m.