Nile crocodile

Nile crocodile, (Crocodylus niloticus), species of crocodile inhabiting freshwater lakes, rivers, and swamps and brackish waters of southern and eastern Africa and Madagascar. The Nile crocodile is the largest crocodile in Africa and one of the largest living reptiles, some individuals rivaling the estuarine (or saltwater) crocodile (C. porosus, which is Earth’s largest living reptile) of Southeast Asia and Australia in both size and weight. The species was thought to have included certain crocodile populations from western sub-Saharan Africa; however, these populations were assigned to its own species, C. suchus, in 2011. Nile crocodiles have a reputation for being fearsome and aggressive, a perspective underscored by hundreds of documented Nile crocodile attacks on people and livestock each year.

Natural history

Although some exceptionally large Nile crocodiles can grow as long as 6 meters (19.7 feet) and weigh more than 680 kg (about 1,500 pounds), they average between 4 and 4.5 meters (13.1 and 14.8 feet) long and weigh about 410 kg (about 900 pounds). Males are larger than females, and, as with all crocodiles, the skin of the Nile crocodile is very thick, with bony plates on their backs, and they have long snouts with powerful jaws, short legs with clawed webbed toes, and a long tail.

The Nile crocodile is an apex predator, and it is one of the most dangerous reptiles in the world. Although a large part of the diet of most adult individuals is made up of fish, many Nile crocodiles also feed on birds, other crocodiles, and mammals (such as wildebeest and other antelopes but also prey as large as young elephants). To catch an animal on land, a Nile crocodile floats silently near the water’s edge with only its nostrils, eyes, and ears above the surface before lunging suddenly to seize and drown its prey by dragging it underwater. Nile crocodiles also eat carrion (dead animals) and human beings. Young crocodiles prey on smaller items, such as fish and crustaceans, along with amphibians and other reptiles. Nile crocodiles are hunted by human beings, and other animals, including baboons and mongooses, prey on their eggs.

Females can become sexually mature after they grow to a length of more than 2 meters (about 6.6 feet), which often occurs by age 10. In contrast, sexual maturity in males occurs between ages 12 and 19. Mating, which occurs once per year, is timed to produce hatchlings at the onset of the rainy season, and a female crocodile can produce a clutch of up to 80 eggs between one and five months after mating. She deposits the eggs in a burrow along a riverbank or sandy shore, covers them with sand or soil, and incubates them until they hatch. Egg incubation temperature during the middle third of the three-month incubation period determines the sex of the young, cooler and warmer temperatures producing females and intermediate temperatures, between 31.7 °C (89.1 °F) to 34.5 °C (94.1 °F), producing males. The young crocodiles will remain with their mother until they gradually disperse starting at three months of age. Nile crocodiles are thought to live between 40 and 60 years in the wild.

Attacks on people

The species is responsible for several hundred confirmed human deaths per year; however, because many attacks occur in rural areas and may go unreported, the true figure may be higher. Most attacks on people occur near the water’s edge, where people wash their clothes, board and exit fishing boats, or walk along the shore. Children are considered at greatest risk due to their small size.

Conservation status

The International Union for Conservation of Nature and Natural Resources (IUCN) considers the Nile crocodile as a species of least concern. Population studies estimate that the species is made up of between 250,000 and 500,000 animals (of which between 50,000 and 70,000 are adults) living in numerous, distinct populations. The species was nearly hunted to extinction during the middle of the 20th century because of hunters seeking trophies, as well as the crocodile’s meat and skin, and killing them in retaliation for attacks on people. Since then, the Nile crocodile’s numbers have increased in most places where they live. Although there are reports of population declines in some areas, such decreases are localized, since most populations are found in protected areas or in areas not frequented by people. Nevertheless, ecologists and wildlife officials note that the species continues to be threatened by habitat loss as natural land is converted to agriculture, hunting and poisoning (which includes the killing of nuisance animals using pesticide-laced baits and retributive killings for attacks on livestock and people), and water pollution from runoff containing mining and industrial waste and agricultural chemicals.