Crocodiles and alligators are called ‘loud-mouths’ because, they are very noisy animals. Even before they hatch, baby crocodiles make calls from within the egg, signaling that hatching time is near. Baby crocodiles have a high pitched yelping cry which they use to call their mother. When an adult crocodile is angry, it makes a long hissing noise or growl.
The sound made by crocodiles and alligators range from coughs and hisses to roars and bellows. Bellowing seems to be contagious. If one animal in a group starts bellowing, others will soon join in and the chorus may go on for up to half an hour! Alligators are believed to recognize each other’s calls, so that they are able to keep track of their friends and foes.