This time I'll share a bit about Crab is a ten-legged crustacean animal from Brachyura's infraorda, known to have a very short "tail" (Greek: brachy = short, ura = tail), or whose abdomen is the same once hidden beneath the chest (thorax). The body of the crab is protected by a very hard shell, composed of chitin, and armed with a pair of claws. Ketam is another name for crab.
Crabs are present in all the oceans of the world. There are also freshwater and terrestrial crabs, especially in tropical regions. The crab is a crab that lives in the waters of the sea and rarely goes to the beach, whereas yuyu is the crab of the inhabitants of freshwater (rivers and lakes).
Crabs of all sizes, from crab beans, only a few millimeters wide, to Japanese spider crabs, with a leg span of up to 4 m [1]. 
