Adults of this species are about 2.2 to 4.7 inches in length. Crayfish are characterized by a joined head and thorax, and a segmented body. In the case of the species Procambarus clarkii, the body is a very dark red color, with a wedge-shaped black stripe on the abdomen. Crayfish have a sharp snout and moveable eyes on their heads. Like all arthropods, crayfish have a thin but tough exoskeleton that they shed during development. Crayfish have 5 pairs of walking legs, the first of which are large pinchers used for feeding. On the red swamp crayfish, the pinchers tend to be narrow and long. They have long antennae with sensory organs on them. This along with appendages used for feeding, are characteristic of the subphylum Mandibulata. There are also five pairs of smaller appendages called swimmerets on the abdomen. The carapace of this species, located on the dorsal side, are not separated by a space. The most posterior pair of appendages are called uropods. Uropods are flat, broad extentions that surround the telson, which is the last abdominal segment. Uropods are also used for swimming (Safra, et al 1999; McDonald 1996; Vodopich and Moore 1999; Barnes 1974).