The Saltwater crocodile and the Nile crocodile are the largest of the 23 crocodilian species. The males grow up to 20 ft (6 metres) long and weigh about a ton. A crocodile’s tongue is attached to the roof of its mouth and it cannot move it, meaning a crocodile cannot chew. It breaks up its food by biting into it and then turning over to tear pieces off, swallowing the food whole, bones and all. Its digestive juices are so strong that it can digest a steel nail.
Crocodiles eat almost anything but prefer meat. Including humans… as can be seen in the photograph. A saltwater croc bit off the hand of a veterinarian at the Shoushan Zoo in Kaohsiung, Taiwan. See the story at National Geographic.
In general there are few human casualties in the croc world – 1 or 2 a year – mostly because people steer away from them. Hippos cause more human deaths than any other animal.
The scales of a crocodile are made of ceratin, the same substance that hooves and fingernails are made of.