The Nile crocodile (Crocodylus niloticus) is a large crocodilian native to freshwater habitats in Africa, where it is present in 26 countries. It is widely distributed in sub-Saharan Africa, occurring mostly in the eastern, southern, and central regions of the continent, and lives in different types of aquatic environments such as lakes, rivers, swamps, and marshlands. It occasionally inhabits deltas, brackish lakes, and rarely also saltwater. Its range once stretched from the Nile Delta throughout the Nile River.
A Nile crocodile emerges from the Mara River.
The binomial name Crocodylus niloticus is derived from the Greek κρόκη, kroke ("pebble"), δρῖλος, drilos ("worm"), referring to its rough skin; and niloticus, meaning "from the Nile River". The Nile crocodile is called timsah al-nil in Arabic, mamba in Swahili, yaxaas in Somali, garwe in Shona, ngwenya in Ndebele, ngwena in Venda, kwena in Sotho and Tswana, and tanin ha-yeor in Hebrew.
Size and Appearance
Generally, the adult male Nile crocodile is between 3.5 and 5 m (11 ft 6 in and 16 ft 5 in) in length and weighs 225 to 750 kg (496 to 1,653 lb). However, specimens exceeding 6.1 m (20 ft) in length and 1,000 kg (2,200 lb) in weight have been recorded. It is the largest predator in Africa and may be considered the second-largest extant reptile in the world, after the saltwater crocodile (Crocodylus porosus). Size is sexually dimorphic, with females usually about 30% smaller than males.
Adult Nile crocodiles have a dark bronze coloration above, with faded blackish spots and stripes variably appearing across the back and a dingy off-yellow on the belly, although mud can often obscure the crocodile's actual color. The flanks, which are yellowish-green in color, have dark patches arranged in oblique stripes in highly variable patterns. Some variation occurs relative to the environment; specimens from swift-flowing waters tend to be lighter in color than those dwelling in murkier lakes or swamps, which provides camouflage that suits their environment, an example of clinal variation. Nile crocodiles have green eyes. The coloration also helps to camouflage them; juveniles are grey, multicoloured, or brown, with dark cross-bands on the tail and body.
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Most morphological attributes of Nile crocodiles are typical of crocodilians as a whole. Like all crocodilians, for example, 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, elongated jaws. Their skin has a number of poorly understood integumentary sense organs that may react to changes in water pressure, presumably allowing them to track prey movements in the water. The Nile crocodile has fewer osteoderms on the belly, which are much more conspicuous on some of the more modestly sized crocodilians.
The species, however, also has small, oval osteoderms on the sides of the body, as well as the throat. The Nile crocodile shares with all crocodilians a nictitating membrane 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 under water. They have a four-chambered heart, although modified for their ectothermic nature due to an elongated cardiac septum, physiologically similar to the heart of a bird, which is especially efficient at oxygenating their blood.
As in all crocodilians, Nile crocodiles have exceptionally high levels of lactic acid in their blood, which allows them to sit motionless in water for up to 2 hours. Levels of lactic acid as high as they are in a crocodile would kill most vertebrates. The mouths of Nile crocodiles are filled with 64 to 68 sharply pointed, cone-shaped teeth (about a dozen less than alligators have). For most of a crocodile's life, broken teeth can be replaced. On each side of the mouth, five teeth are in the front of the upper jaw (premaxilla), 13 or 14 are in the rest of the upper jaw (maxilla), and 14 or 15 are on either side of the lower jaw (mandible). The enlarged fourth lower tooth fits into the notch on the upper jaw and is visible when the jaws are closed, as is the case with all true crocodiles. Hatchlings quickly lose a hardened piece of skin on the top of their mouths called the egg tooth, which they use to break through their eggshells at hatching.
Bite Force
The bite force exerted by an adult Nile crocodile has been shown by Brady Barr to measure 22 kN (5,000 lbf). However, the muscles responsible for opening the mouth are exceptionally weak, allowing a person to easily hold them shut, and even larger crocodiles can be brought under control by the use of duct tape to bind the jaws together.
Distribution and Habitat
The Nile crocodile's current distribution extends from the regional tributaries of the Nile in Sudan and Lake Nasser in Egypt to the Cunene River in Angola, the Okavango Delta of Botswana, and the Olifants River in South Africa. It is the most common crocodilian in Africa and occurs in Somalia, Ethiopia, Uganda, Kenya, Central African Republic, the Democratic Republic of the Congo, Equatorial Guinea, Tanzania, Rwanda, Burundi, Zambia, Zimbabwe, Gabon, Malawi, Mozambique, Namibia, Sudan, South Sudan and Cameroon.
Its historic range extended to the Mediterranean coast in Libya, Tunisia, Algeria, Morocco and across the Red Sea in the Palestine region and Syria. Herodotus sighted it in Lake Moeris in Egypt. It is thought to have become extinct in the Seychelles in the early 19th century. The Nile crocodile was previously thought to also occur in West and Central Africa, but these populations are now typically recognized as a distinct species, the West African (or desert) crocodile.
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Distribution map of the Nile Crocodile.
Diet and Behavior
Nile crocodiles are opportunistic apex predators; a very aggressive crocodile, they are capable of taking almost any animal within their range. They are generalists, taking a variety of prey, with a diet consisting mostly of different species of fish, reptiles, birds, and mammals. As ambush predators, they can wait for hours, days, and even weeks for the suitable moment to attack. They are agile predators and wait for the opportunity for a prey item to come well within attack range. Even swift prey are not immune to attack. Like other crocodiles, Nile crocodiles have a powerful bite that is unique among all animals, and sharp, conical teeth that sink into flesh, allowing a grip that is almost impossible to loosen.
Nile crocodiles often prey on animals drinking at the water’s edge, such as antelopes. They spend much of their day in the shallows or basking in the sun with their mouths open. These massive males always get the best basking spots and have food access before others do. The snout of a crocodile is a sensory array, extremely fine-tined to pressure and movement. By some metrics, they’re more sensitive than human fingers, and this precision combines with the immense bite force to help bring down large prey quickly.
Nile crocodiles are relatively social amongst themselves. They share basking spots and large food sources, such as schools of fish and big carcasses. Their strict hierarchy is determined by size. Large, old males are at the top of this hierarchy and have first access to food and the best basking spots.
Reproduction
During mating season, males attract females by making a lot of noise. They do this by blowing water out of their noses and slapping it with their snouts. On average, they lay between 25 and 80 eggs. Most other crocodiles cover their eggs with rotting leaves and vegetation, which is a good source of heat.When it is time for the eggs to hatch they dig open the nest and help the young crocodiles out of the eggs. Female crocodiles do this by picking up the eggs and rolling them in their mouths to crack the shells. Sometimes, they even carry the newly hatched crocodiles to the water in their mouths. Newly hatched Nile crocodiles are only around 12 inches long when they are born.
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The Infamous Gustave
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In the heart of Central Africa, where the Ruzizi River spills into the vast waters of Lake Tanganyika, there is a creature so fearsome, that his very name sends shivers down the spines of locals. That creature is Gustave-a Nile crocodile of monstrous proportions, a predator with a rumored body count of over 300 people and a phantom that has eluded capture for decades. His legend inspired the 2007 Hollywood horror film Primeval, but for the people of Burundi, Gustave is anything but fictional. He is real. He is brutal. And he may still be out there.
The infamous Gustave.
While the average male grows to around 13-16 feet (4-5 meters) and weighs about 900 pounds (410 kg), Gustave is estimated to be at least 20 feet (6.1 meters) long and tip the scales at over 2,000 pounds (907 kg). This makes him one of the largest Nile crocodiles ever recorded. His estimated age is over 60 years. Though he may not be as ancient as Henry, the 124-year-old father to 10,000 Nile crocodiles in South Africa, Gustave has still lived long enough to terrorize multiple generations. With a body so massive, Gustave’s size likely hinders his ability to hunt quick-moving prey like fish or antelope, pushing him toward larger, slower animals-including humans.
Unlike most crocs that blend into the murky waters, he bears three bullet scars and a deep wound on his right shoulder blade, all signs of past attempts to kill him. Yet, despite being shot at by hunters, soldiers and even a reported machine-gun ambush, he has survived every encounter. Gustave never fell for the trap. At one point, a live goat was placed inside the cage, but after a stormy night, the team returned to find the cage partially submerged and the goat gone. Whether Gustave was responsible remains a mystery.
Gustave’s last confirmed sighting was in 2009, and though reports surfaced in 2019 claiming he had been killed, no photographic evidence or carcass has ever been found. Some believe he may have succumbed to old age, while others insist he is still alive, lurking beneath the surface, waiting for his next victim.
Nile Crocodile Facts Overview
| Category | Details |
|---|---|
| Common Name | Nile Crocodile |
| Scientific Name | Crocodylus niloticus |
| Type | Reptile |
| Diet | Carnivore |
| Group Name | Bask (on land), float (in water) |
| Average Life Span In The Wild | 45 years |
| Size | Up to 5 meters long |
| Weight | Can exceed 1,000kg |
| Colour | Brown/Yellow, sometimes green |
| Habitat | Rivers and lakes |
| Location | Africa |
| Predators | None/sometimes humans |
| Top Speed | 4 km/h (8.7 mph) |
| Conservation Status | Least Concern (IUCN) |
