The Nile crocodile (Crocodylus niloticus) is a large crocodilian native to freshwater habitats in Africa, where it is present in 26 countries. Due to its widespread occurrence and stable population trend, it has been listed as Least Concern on the IUCN Red List since 1996. It is widely distributed throughout sub-Saharan Africa, occurring mostly in the central, eastern, and southern regions of the continent, and lives in different types of aquatic environments such as lakes, rivers, and marshlands. Although capable of living in saline environments, this species is rarely found in saltwater, but occasionally inhabits deltas and brackish lakes. The range of this species once stretched northward throughout the Nile, as far north as the Nile delta. On average, the adult male Nile crocodile is between 3.5 and 5 m in length and weighs 225 to 750 kg. However, specimens exceeding 6.1 m in length and weighing up to 1,090 kg have been recorded. It is the largest freshwater predator in Africa, and may be considered the second-largest extant reptile and in the world, after the saltwater crocodile (Crocodylus porosus). Sexual dimorphism is prevalent, and females are usually about 30% smaller than males. They have thick, scaly, heavily armored skin.
Crocodiles have the strongest bite in the animal kingdom. And the Nile crocodile is no different. It's bite can exert a force eight times more powerful than that of a great white shark and 15 times more than a Rottweiler’s. Powerful muscles for closing the jaws, however, contrast with small, weak ones for opening them.
Female crocodiles exhibit impressive maternal care. They use their massive jaws to transport newly hatched young to a ‘nursery pool’ where they guard them from predators.
The sex of crocodile hatchlings is determined by the temperature at which the eggs incubate. At 30ºC or less they will be mostly female; at 31ºC they will be mixed; and at 32ºC, they will be mostly male.
Crocodiles are the most vocal of reptiles. Among more than five different calls are the deep, vibrating bellow of courting males and the ‘peeping’ of babies inside the egg. This 'peeping' encourages the female to excavate the nest.
Large crocodiles swallow stones, known as gastroliths. These act as ballast, helping them to balance their body underwater.
The Nile crocodile (Crocodylus niloticus) is a large freshwater African reptile. It is responsible for the most deaths from any animal as a predator preying on humans, yet crocodiles serve an important ecological function. The Nile crocodile eats carcasses that pollute water and controls predatory fish that could overeat smaller fish used as food by many other species.