Overview
Along a sunlit riverbank, the dark outline of a Nile crocodile may lie almost completely motionless. With only its eyes and nostrils above the surface, this ancient predator can watch its surroundings while remaining almost invisible to nearby prey.
Nile crocodiles inhabit many of Tanzania’s major rivers, lakes and wetlands, including the Mara and Grumeti rivers, where they are famously seen during wildebeest crossings. Fish make up much of their diet, but large adults can also take birds, reptiles and mammals that approach the water’s edge.
Their hunting strategy relies on patience, camouflage and explosive force. A crocodile may wait beneath the surface before surging forwards, gripping prey with powerful jaws and pulling it into deeper water. Although immense males can exceed five metres, most adults encountered in the wild are smaller.
Behaviour & How to Identify
Look for a large, heavily armoured reptile with a broad snout, powerful tail and raised bony scutes along the back. Adults are generally dark olive, grey or brown, while younger crocodiles have clearer dark bands across the body and tail.
The eyes, ears and nostrils are positioned high on the head, allowing the crocodile to remain almost entirely submerged while still seeing, hearing and breathing. A transparent third eyelid protects the eyes underwater, while valves close the ears and nostrils during a dive.
Females dig nests in sand or soil above the waterline and remain nearby during incubation. When the hatchlings begin calling from inside the eggs, the mother may uncover the nest and gently carry the young to water in her jaws. She may continue guarding them during their vulnerable early lives.
Interesting facts
They can ambush prey with barely a ripple. Their eyes and nostrils remain above water while almost the entire body stays concealed below the surface.
Their jaws are built for gripping rather than chewing. Crocodiles tear large food items apart by twisting the body in a manoeuvre commonly called a death roll.
Mothers respond to calls from inside the eggs. The hatchlings begin vocalising before they emerge, prompting the female to uncover the nest and help them reach the water.