Williams’ Crayfish

Faxonius williamsi (formerly Orconectes williamsi)


Photo of Williams' crayfish.
Williams’ crayfish is found only in the upper White River drainage of Missouri and Arkansas.
Chris Lukhaup
Species of Conservation Concern

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


Williams' crayfish is a small, rather plain crayfish without bright colors or bold markings. Its most distinctive feature is a pale, vase-shaped zone along the middle of the dark olive-tan carapace. The pincers are broad and powerful.

Similar species within the range of Williams’ crayfish are the Ozark crayfish, which has numerous dark specks on the pincers and abdomen, and the ringed crayfish, which has prominent black or brown rings near the tips of the fingers. These species reach a larger size than Williams’ crayfish.


Adult length: about 1¼ to 2 inches.

Habitat and conservation

Inhabits clear, rocky and gravelly headwater creeks, spring branches, and cave streams. It excavates burrows beneath large rocks in gravelly and sandy substrates.


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

Williams' Crayfish Distribution Map
Distribution in Missouri

Williams’ crayfish occurs in the White River basin of Missouri and Arkansas and has been recorded in Roaring River and a few other streams of southern Barry, Stone, Christian, and Taney counties.


Imperiled in Missouri, due to its very localized distribution. A Species of Conservation Concern in Missouri.

Life cycle

Very little is known about the reproduction of this species. Most other Ozark stream crayfish mate in the fall and bear eggs in the spring. The female carries the eggs, then the young, beneath her abdomen, until the young are capable of living independently. Most of our crayfish only live to be a few years old.

Human connections

Crayfish are colorful and interesting animals. They are important members of aquatic communities, influencing the health of ponds, lakes, and streams and therefore contributing to the success of anglers, froggers, and bird watchers.

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.