Crayfish

Crayfish are characterized by a joined head and thorax, or midsection, and a segmented body, which is sandy yellow, green, red, or dark brown in colour. The head has a sharp snout, and the compound eyes are on movable stalks. The exoskeleton, or body covering, is thin but tough. Crayfish activity centers around food. When food sources are abundant, a crayfish tends to forage (i.e. leave its refuge under a rock or log) a very small percentage of the time. When food is scarce, though, crayfish will spend a considerable amount of time foraging. Crayfish consume both plant and animal materials and will, depending upon seasonal and local availabilities, consume a great variety of types of foods. Almost all aquatic plants, mollusks, insect larvae, mature insects, tadpoles, ambian eggs, and small fish are common foods. Also taken opportunistically are small rodents and even small birds. Young crayfish must consume 1 to 4% of their body weight each day and tend to concentrate upon animal food sources. Adult crayfish, on the other hand, only require an intake of 0.3 to 1% of their body weight each day and tend to primarily take plant materials for their food. If living food sources are not available, crayfish will, at need, consume carrion. Crayfish tend to forage for food at night