Virile crayfish

Conservation Status

IUCN Red List

LC - Least Concern

NatureServe

N5 - Secure
SNR - Unranked

Minnesota

not listed

Description

Virile crayfish, also called northern crayfish, is a medium- to large-sized freshwater crustacean. It is widespread and abundant across North America. It is native to central United States and Canada from Quebec to Tennessee in the east to Alberta and Colorado in the west. It is introduced and considered invasive outside of its native range from coast to coast.

Adults are 1¾″ to 5″ long and smooth. Males are usually larger than females. Occasionally, an individual will be entirely bluish.

The abdomen and the shield (carapace) covering the front part of the body (cephalothorax) are olive-brown dappled with dark brown. The long spike-like extension of the carapace that projects forward between the eyes (rostrum) has straight, more or less parallel sides. There is a pair of dark brown splotches on the upper (dorsal) side of abdominal segments 1 through 5.

The claws (chelae) are broadly flattened and usually bluish with numerous yellow bumps (tubercles). They do not have black bands at the tip. The movable finger (dactylus) on the claw has a straight margin. The legs are usually bluish with yellow tubercles.

Size

Total length: 1¾″ to 5″

Similar Species

Habitat

A variety of lakes, streams, and wetlands

Ecology

Season

Most active May to September

Behavior

They prefer streams with rocky bottoms, moderate flow and turbidity, abundant cover, and stable water levels. They often use rocks, logs, or other organic debris as cover. They occasionally dig burrows into muddy banks, especially when water levels are low.

To survive the winter, they migrate to deeper water that does not completely freeze and they become inactive.

Lifespan

3 to 4 years

Life Cycle

Breeding takes place in the fall or early spring. The female stores the sperm, sometimes for months, and fertilizes the eggs in the spring. The fertilized eggs are attached is raspberry-like bunches to the abdominal appendages (swimmerets). They hatch in one to two months. They moult several times and reach maturity in their second year.

Juvenile Diet

Adult Diet

Mostly dead animals, but also living snails, insects, fish, tadpoles, and plant material.

Distribution

Sources

24, 30, 82, 83.

Biodiversity occurrence data published by: Minnesota Biodiversity Atlas (accessed through the Minnesota Biodiversity Atlas Portal, bellatlas.umn.edu. Accessed 7/11/2026).

Faxonius virilis (Hagen, 1870) in Bánki, O., Roskov, Y., Döring, M., Ower, G., Hernández Robles, D. R., Plata Corredor, C. A., Stjernegaard Jeppesen, T., Örn, A., Pape, T., Hobern, D., Garnett, S., Little, H., DeWalt, R. E., Miller, J., Orrell, T., Aalbu, R., Abbott, J., Abreu, C., Acero P, A., et al. (2026). Catalogue of Life (2026-06-19 XR). Catalogue of Life Foundation, Amsterdam, Netherlands. https://doi.org/10.48580/dgy8b

Helgen, J.C. 1990. The distribution of crayfishes (Decapoda, Cambaridae) in Minnesota. Final report submitted to the Nongame Wildlife Program, Minnesota Department of Natural Resources. 96 pp.