The Order Decapoda is a group of crustaceans that includes crabs, lobsters, shrimp, and crayfish. Members are characterized by having ten legs (five pairs of thoracic appendages), a hard exoskeleton, and a segmented body divided into a cephalothorax and abdomen. Decapods are found in marine, freshwater, and some terrestrial environments and exhibit diverse feeding habits, including scavenging, predation, and filter-feeding. Many species are ecologically and economically important, serving as key components of aquatic food webs and as a major source of seafood worldwide.