The Nile crocodile (Crocodylus niloticus) is an African crocodile and may be considered the second largest extant reptile in the world, after the saltwater crocodile (Crocodylus porosus). The Nile crocodile is quite widespread 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 Nile crocodile can range between 2.8 and 5 m (9 ft 2 in and 16 ft 5 in) in length and weigh around 70 to 700 kg (150 to 1,540 lb). However, specimens exceeding 6.1 m (20 ft 0 in) in length and weighing more than 907 kg (2,000 lb) have been recorded. They have thick scaly skin that is heavily armored.
The Nile crocodile is an opportunistic apex predator and a very aggressive species of crocodile that is capable of taking almost any animal within its range. They are generalists, taking a variety of prey. Their diet consists mostly of different species of fish, reptiles, birds and mammals. The Nile crocodile is an ambush predator and can wait for hours, days and even weeks for the suitable moment to attack. They are quite agile predators and wait for the opportunity for the prey item to come close within the range of attack. Even swift prey are not immune to attack. Like other crocodiles, Nile crocodiles have an extremely powerful bite that is unique amongst all animals and sharp conical teeth that sink into flesh allowing for a grip that is almost impossible to loosen. They can apply high levels of force for extended periods of time, a great advantage for holding down large prey underwater to drown.
Nile crocodiles are relatively social crocodiles. They share basking spots and large food sources such as schools of fish and big carcasses. There is a strict hierarchy, that is determined by size. Large, old males are at the top of this hierarchy and have primary access to food and the best basking spots. Crocodiles know their place in the hierarchical order and rarely act against it, but when they do, the results are very bloody and sometimes even fatal. Like other reptiles, Nile crocodiles lay eggs to reproduce, which are guarded by the female. The hatchlings are also protected for a period of time, but hunt by themselves and are not fed by the parents. The Nile crocodile is one of the most dangerous species of crocodile and is responsible for hundreds of deaths of humans every year It is a rather common species of crocodile and is not endangered despite some regional declines or extinctions.