Crabs are crustaceans that inhabit both fresh and salt water. These animals have a hard, segmented body. They are characterized by a wide, flattened body, with two large claws at the front and four pairs of legs on the lower body.
Crab claws can vary in size and shape depending on the species, and are used for defense and to capture food. They feed mainly on algae, small animals and organic debris.
There are many different species and the size varies according to the species. Some of the best known are the blue crab, crayfish, snow crab and king crab.