The Nile Crocodile is one of the three species of crocodile found in Africa, and the second largest species of crocodile. Its range covers most of Africa south of the Sahara and the island of Madagascar. The preferred habitat of Nile crocodiles is along rivers, in freshwater marshes, or along lakes. In some cases they thrive in more brackish water, along estuaries of mangrove swamps.
Like all crocodiles, they are quadrupeds with four short, splayed legs; long, powerful tails; a scaly hide with rows of ossified scales running down their back and tail; and mighty jaws. They have eyelid-like membranes to protect their eyes, and despite the myths they do have tear ducts, and can cleanse their eyes with tears. Their nostrils, eyes, and ears are situated on the tops of their head, so the rest of the body can remain concealed underwater. Their coloration also helps them hide. The young are gray, dark olive, or brown; with darker cross-bands on their tail and body. As they mature they become darker and the cross-bands fade, especially those on the body. The underbelly is yellowish, and makes high-quality leather.
The Nile Crocodile is the largest African crocodile, reaching lengths of up to 16 feet, and rarely up to 20 feet. A good sized male weighs about 1100 pounds, and a truly exceptional specimen can exceed 2400 pounds. Males are 30% larger than females. Nile crocs are normally belly crawlers, but can walk on their feet. Smaller crocs can gallop and are capable of short bursts of speed, up to 8 mph. They are fast quick swimmers as well and can maintain its speed for a long period of time in the water.
They have a four-chambered heart, like a bird, which is especially efficient at oxygenating their blood. They normally dive for only a couple of minutes, but will stay underwater for up to 30 minutes if threatened, and if they remain inactive they can hold their breath for up to 2 hours. They have a rich vocal range, and good hearing. Their skin has a number of poorly-understood sensory organs that may react to changes in water pressure.
Their jaws are capable of exerting impressive force as they hold on to their prey. Their mouths are filled with a total of 64 to 68 cone-shaped teeth. On each side of the mouth, there are 5 teeth in the front of the upper jaw, 13 or 14 in the rest of the upper jaw (the maxilla), and 14 or 15 on either side of the lower jaw (the mandible). Hatchlings quickly lose a hardened piece of skin on the top of their mouth called the egg tooth, which they use to break through their egg’s shell at birth.
Nile crocs reach sexual maturity at about 10 years of age. During the mating season, males attract females by bellowing, slapping their snouts in the water, blowing water out of their noses, and making a variety of other noises. Larger and older males tend to be more successful. Once the female has been attracted, the pair warble and rub the underside of their jaws together. The female will lay their eggs about 2 months after mating.
Preferred nesting locations are sandy shores, dry stream beds, or riverbanks. The female then digs a hole a few yards away from the bank and up to 20 inches deep., and lays between 25 and 80 eggs. The number of eggs varies between different populations, but averages about 50. Multiple females may nest together. Once the eggs are laid, the female covers them over with sand and guards them for the 3 month incubation period. Sometimes the male will stay nearby as well and fiercely attack anything that approaches their eggs.
The hatchlings start to make a high=pitched chirping noise before they hatch, which is the signal for the mother to rip open the nest. Both mother and father may pick up the egg in their mouths and roll them between their tongue and upper palate to help crack the shell. Once the eggs are hatched, the mother may either lead or carry the young in her mouth to the water. She will care for them for two years before they naturally depart and go out on their own.
The Nile Crocodile is known as a man-eater and has been hated, revered, and worshipped. This croc can, and sometimes will, easily snatch and devour a human. Adult crocodiles have also been known to eat zebras, young hippos, buffalo, rhinos, warthogs, hyenas, baboons, antelope, giraffe, big cats, and even other crocodiles. Once their prey is dead, they rip off and swallow chunks of flesh. When groups of Nile crocodiles are sharing a kill, they use each other for leverage, biting down hard and then twisting their body to tear off large pieces of meat. This is called the death roll. They may also get the necessary leverage by lodging their prey under branches or stones, before rolling and ripping.