Crocodiles differ from Alligators from the way their teeth are arranged. When a croc closes its mouth two mandibular teeth are visible. In alligators teeth are not visible.
Crocs have clawed feet and webbed hind feet which make them masters, both in water and on land. They incredibly Fast in water and can reach speeds of 17 km/h.
The tail of a crocodile is a very powerful rudder which propels it in the water. The tail is also used for another unlikely prop and that is too store fat during droughts.
The Nile Crocodile digs whole nests up to 50cm deep in sandy banks, several meters from the water. These may be in close proximity to other nests.