Belted Crayfish (Big River Crayfish)

Faxonius harrisonii (formerly Orconectes harrisonii)


Photo of a belted crayfish, also called Big River crayfish.
The belted crayfish, or Big River crayfish, is found only in the Big River and its tributaries, and the Meramec below the mouth of the Big River.
Chris Lukhaup
Species of Conservation Concern

Cambaridae (freshwater crayfish) in the order Decapoda (shrimp, crabs, and lobsters)


The belted crayfish is a medium-small, tan crayfish with a distinctive pattern of alternating olive-green and reddish-brown bands on the abdominal segments. Another unique feature is the presence on the carapace of a broad, blackish band that spans the cervical groove (the groove separating head and thorax). A second blackish band is located at the junction of the carapace and abdomen. The pincers are narrow for a stream crayfish but are not especially long.

Similar species: Within the belted crayfish's range, neither the golden crayfish (F. luteus) nor the saddleback crayfish (F. medius) has the first of the blackish saddle marks spanning the cervical groove.


Adult length: 1½ to 2½ inches.

Habitat and conservation

The belted crayfish inhabits clear, permanent streams ranging from medium-sized creeks to large rivers. It prefers permanent flow, no strong current, and a substrate of coarse rock. In daylight, this active, agile species usually hides beneath rocks. It forages at night.


Crayfish are generally omnivores, feeding on a wide variety of plant and animal materials.

Belted or Big River Crayfish Distribution Map
Distribution in Missouri

Occurs in the Big River and its tributaries of the eastern Ozarks. Also occurs in the Meramec River, just downstream from the mouth of the Big River.


Found only in Missouri's eastern Ozarks, and nowhere else in the world (that is, it is endemic to Missouri). It is a Species of Conservation Concern in Missouri, since it is vulnerable to extinction. Its global ranking is the same.

Life cycle

Mating usually occurs in the fall, and males typically have a different body form, with specialized reproductive structures, in fall and winter. Females usually lay eggs in the spring, adhering them with a gluelike substance to the swimmerets under the abdomen. After hatching, the young remain attached to their mother’s swimmerets until they have completed 2 molts. They then begin making brief forays away from the mother but return to the safety of her abdomen if they feel threatened.

Human connections

Crayfish are colorful and interesting animals. They are important members of aquatic communities, influencing the health of ponds, lakes, and streams and contributing to the success of anglers, froggers, and bird watchers. Crayfish are used for fishing bait. Some species are eaten by people.

Ecosystem connections

Crayfish are an important link in the food chain between plants and other animals, breaking down plant materials that are resistant to decay. They are an important food for many animals that occur around or in water, including fish, snakes, turtles, wading birds, raccoons, and mink.