Shrimps Crabs and Lobsters: Decapoda

Physical characteristics: The dark red, nearly black body of the red swamp crayfish measures up to 4.7 inches (120 millimeters). Its pincherlike claws are long and slender, with bright bumps and red tips.

Geographic range: Originally from the southern United States and northern Mexico only, this species is now widely established in Europe, Africa, Central and South America, and Southeast Asia.

Habitat: This species is tolerant of a wide range of habitats, even slightly salty water. They prefer to live in slow moving streams, swamps, and ponds, where there are plenty of plants growing along the shores and leaves on the bottom. Their populations are the largest in habitats that flood each year.

Diet: Red swamp crayfishes are omnivorous and eat many different kinds of plants and small animals, such as snails, insects, fishes, and tadpoles.

The red swamp crayfish is tolerant of a wide range of habitats, even slightly salty water. (Gerard Lacz/Peter Arnold, Inc.)

Behavior and reproduction: During the dry season they will sometimes dig burrows down 2 feet (0.6 meters) or more to reach water.

Adult males have two body forms. The first form has large claws, hooks at the bases of some legs, and spends its time looking for a mate. After mating, males molt into the second form, which has smaller claws. Females can store sperm for long periods of time. They brood their eggs for two to three weeks and produce two generations each year. The hatchlings resemble small crayfishes and stay with the female for several weeks. They live for a total of twelve to eighteen months in the wild.

Red swamp crayfishes and people: This species is sold as a pet and as fish bait. It has been introduced around the world because it grows fast and can live in a wide variety of habitats. Red swamp crayfishes were introduced to eastern Africa to eat snails that carry parasites harmful to humans.

Conservation status: The World Conservation Union (IUCN) does not consider this species to be threatened or endangered. ∎