Their jaws exert 5000 pounds or 2268 kg of pressure per square inch.  Because of this, anything that enters the crocodile's jaws does not come out easily.  And if it ever comes out, it must come out in two pieces.  The bite of crocodile teeth is stronger than the bite of shark teeth.  Their tails are also very strong and they strike with their tails.  There are slight differences between crocodiles and alligators.