Most crustaceans are marine, meaning they live in the seas and oceans. Some species, however, have their habitat in freshwater, and still others are terrestrial, such as the Garden Peacock. We can cite as examples of better known crustaceans: Shrimp, lobster, crab, crab and barnacle. The size of these animals varies greatly from one species to another.
The body of crustaceans is divided into cephalothorax, body part consisting of fused head and chest, and abdomen.
These animals have a variable number of paws (usually five pairs) and two pairs of antennas. The exoskeleton of many crustaceans has calcium carbonate, a substance that forms the hard shell of crabs and crabs.