The Nile Crocodile is an African crocodile which is common in Somalia, Ethiopia, Uganda, Kenya, Egypt, Tanzania, Zambia, Zimbabwe, Gabon, South Africa, Malawi, Sudan, South Sudan, Botswana, and Cameroon. Isolated populations also exist in Madagascar and in Senegal. The Nile crocodile is the largest crocodilian in Africa and is sometimes regarded as the second-largest crocodilian after the saltwater crocodile.
Nile crocodiles have a dark bronze coloration above, with black spots on the back and a dirty purple on the belly. The flanks, which are yellowish-green in color, have dark patches arranged in oblique stripes. There is some variation relative to environment; specimens from swift-flowing waters tend to be lighter in color than those dwelling in lakes or swamps. They have green eyes.
Like all crocodiles, the Nile crocodile is a quadruped with four short, splayed legs, a long, powerful tail, a scaly hide with rows of ossified scutes running down its back and tail, and powerful jaws. It has nictitating membranes to protect the eyes and lachrymal glands to cleanse its eyes with tears. The nostrils, eyes, and ears are situated on the top of the head, so the rest of the body can remain concealed underwater. The coloration also helps to camouflage it ; juveniles are grey, multicolored, or brown, with dark cross-bands on the tail and body. As it matures, it becomes darker and the cross-bands fade, especially those on the body. The underbelly is yellowish green, and makes high-quality leather.
In antiquity, Nile crocodiles occurred in the Nile Delta and the Zarqa River (Jordan), and they are recorded by Herodotus to have inhabited Lake Moeris. They are thought to have become extinct in the Seychelles in the early 19th century. They are known from fossil remains to have once inhabited Lake Edward. The Nile crocodile's current range of distribution extends from the Senegal River, Lake Chad, Wadai and the Sudan to the Cunene and the Okavango Delta. In Madagascar, crocodiles occur in the western and southern parts from Sembirano to Port Dauphin. They have occasionally been spotted in Zanzibar and the Comoros. Until recently, many permanent waters in the Sahara still housed relict populations.
In East Africa, they are found mostly in rivers, lakes, marshes, and dams. They have been known to enter the sea in some areas, with one specimen having been seen 11 kilometers (6.8 mi) off St Lucia Bay in 1917. In Madagascar, they have adapted to living in caves.
The species was previously thought to extend into West Africa, but these populations are now recognized as a distinct species, the desert crocodile.
Young hatchlings generally feed on smaller prey, preferring insects and small aquatic invertebrates before taking on fish, amphibians and small reptiles. Juveniles and subadults take a wider variety of prey with additions such as birds and small to mid-sized mammals. Throughout their lives, both young and mature crocodiles can feed on fish and other small vertebrates on separate occasions, when large food is absent, as a side diet. Adults are apex predators and prey upon various birds, reptiles and mammals, in addition to prey consumed also by the young and juvenile specimens. Among the mammals, prey consists of gazelles, antelope, hyenas, waterbuck, sitatunga, lions, leopards, lechwe, rhinos, wildebeest, zebras, warthogs, hippos, giraffes, Cape buffalos, and elephants. When given the chance, they are known to prey on domestic chickens, goats, sheep and cattle. Nile crocodiles also prey on humans frequently, far more often than other crocodilian species (although in parts of the Philippines and New Guinea, saltwater crocodile attacks can also be common). Although not common, crocodiles can also hunt in packs of five or more individuals while in the water, which can lead to the capture of much larger prey such as hippopotamus and even the black rhinoceros.