Nile Crocodile is found in the perennial rivers of Botswana including the Okavango, Linyanti, Chobe and Limpopo systems.
Crocodiles are covered in large olive green to grey scales on the back, a yellow belly and black bands across the tail; they can reach in excess of 6m in length (40% of this is the tail) and weigh up to 1000kg
The eyes and nose and ears sit proud of the rest of the head; this adaptation allows a crocodile to keep these sensing organs above water whilst the rest of the body is submerged.
The upper jaw is fused with the rest of the skull and only the lower jaw can move independently. The head must be lifted to allow the bottom jaw to fall open (“mouth-gaping”) when basking in the sun.
These reptiles lack the vomeronasal organ.
Their sharp teeth are used to keep a firm grip on the prey. The 64-68 teeth are frequently replaced. It has a long, spear-shaped tail, short legs and webbed hind feet. The oar like tail allows this reptile to move swiftly through the water using the webbed back feet as rudders.
Although not true of other reptilia, the crocodile, in line with mammals and birds, has a four-chambered heart.
Because the thick hide of the crocodile does not allow the fast transfer of the heat from the sun to the blood, the animal lies on the bank with its mouth open allowing the soft membrane to absorb heat and circulate it to the rest of the body.