The Nile crocodile is one of the 3 species of crocodiles 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. Known as a man-eater, it has been both hated, revered (especially in Ancient Egypt where crocodiles were mummified), and worshipped. The Nile crocodile can, and sometimes will, easily snatch and devour a human. While it is no longer threatened with extinction as a species, the population in many countries is in danger of vanishing.

Like all crocodiles, they are quadrupeds with four short, splayed legs; long, powerful tails; a scaly hide with rows of ossified scutes running down their back and tail; and mighty jaws. They have nictitating membranes to protect their eyes, and despite the myths they do have lachrymal glands, and can cleanse their eyes with tears.
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: Juveniles are grey, 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.
They normally crawl along on their belly, but they can also "high walk". Smaller specimens can gallop, and even larger crocodiles are capable of surprising bursts of speeds, briefly reaching up to 12 to 14 km/h (7.5 to 8.5 mi/h). They can swim equally fast by moving their body and tail in a sinouous fashion, but they can sustain this form of movement much longer.
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 an ectothermic metabolism, so they can survive a long time between meals — though when they do eat, they can eat up to half their body weight at a time.
They have a rich vocal range, and good hearing. Their skin has a number of poorly-understood integumentary sense organs (ISOs), 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 (the premaxilla), 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.

Information source

Photographed in Ewaso Ngiro River of the Shaba National Reserve, Juliol de 2006.