Crocs are grayish-green possibly to reflect sunshine. Alligators are grayish-black. This could possibly to absorb the sunshine. C. Climate preferences Crocodiles live in hotter climates. D. Nest building techniques Crocodiles dig holes to lay eggs.
Alligators build mounds.
E. Temperament differences Crocodiles have watched humans grow up and understand humans can be food. Alligators don't normally eat people. Since they have been both isolated from humans for all but about 5 or 6 thousand years, they don't really understand we're on the menu, unless we teach them. F. Smiles on their faces Crocodiles have a toothy grin when their mouths are closed. You see both top teeth and bottom teeth.