Crayfishes

About 36 species in Missouri

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Photo of a spothanded crayfish viewed from above on white background.
This picture of a spothanded crayfish shows many features of crayfish anatomy.
Jim Rathert
Family

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

Description

Crayfish are not likely to be confused with any other Missouri animals. The lobster-like body, including the tail fan flattened top to bottom, distinguishes them from their closest relatives in Missouri, two species of freshwater shrimp.

To identify the different species, learn the names of crayfish body parts. Ten appendages are obvious: 4 pairs of walking legs plus 1 pair of pincers (chelipeds) (each pincer has a thumblike movable finger attached to a “palm”). The body is divided into 2 main parts: at the front is the domelike carapace, comprising both head and thorax and to which the legs attach; and the abdomen, which is the obviously segmented hind part of the body, like the meaty “tail” of a lobster. The shallow indentation between the head and thorax is the cervical groove. At the front of the head are 2 pairs of “feelers”: 1 pair of antennae (the long ones) and 2 pairs of antennules (the short ones). The triangular extension of the carapace between the eyes is the rostrum.

Size

Length (front of head to tip of tail): Depending on species, adult size ranges from 7/8 inch to more than 6 inches. (Length excludes antennae and legs.)

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Photo of a Mammoth Spring crayfish hiding under a rock.
Mammoth Spring Crayfish
Like many other crayfishes, the Mammoth Spring crayfish hides beneath rocks.

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Photo of the eggs under abdomen of female northern crayfish.
Female Northern Crayfish Carrying Eggs
Female crayfish carry their eggs and newly hatched young on the underside of the abdomen.

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Photo of a golden crayfish showing pincers.
Golden Crayfish Pincers
The pincers of golden crayfish are moderately heavy and broad.

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Photo of a northern crayfish showing pincers.
Northern Crayfish Pincers
On northern crayfish, the inner margins of the pincers have prominent yellowish knobs or tubercles.

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Photo of a grassland crayfish, also called prairie crayfish.
Grassland Crayfish (Prairie Crayfish)
The grassland crayfish inhabits prairies and grasslands in northern and western Missouri.

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Photo of a bristly cave crayfish, viewed from the side.
Bristly Cave Crayfish
The bristly cave crayfish lives in caves in the Springfield Plateau region of the Ozarks.

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Video of cave crayfish.
Habitat and conservation

Our diverse crayfish species are adapted to a variety of habitats, including streams with noticeable current; swamps, marshes, and ponds, without currents; caves and springs; and burrowing in the ground, sometimes considerable distances from water, or in temporarily flooded land. Crayfish adapted to permanently flowing streams rarely travel overland; therefore, certain species are fairly restricted to certain drainage systems. Burrowing crayfish tend to live in grasslands and floodplains.

Foods

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

image Crayfishes Distribution Map
Distribution in Missouri

Crayfish occur throughout Missouri, but the greatest variety of species occurs in the Ozarks, where the many separate stream systems carry entirely different species. Some 25 of our approximately 35 crayfish species live in the Ozarks.

Status

There are about 450 species in North America, and about 35 in Missouri. Nineteen species are Missouri Species of Conservation Concern, meaning they are imperiled or vulnerable within our borders. On the other hand, other species are robust, prolific, and may be farm-raised for human food or as fish food or bait. Some are invasive. In Missouri you can harvest any but the protected species, following regulations for live bait. You cannot release crayfish anywhere other than where you caught them.

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

In addition to feeding many types of wildlife, crayfish provide food for many species that humans hunt and fish. Crayfish commonly serve as fish bait, and many people eat crayfish, too. Crayfish are fascinating, colorful creatures in their own right, and part of our rich native heritage.

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. Crayfish in turn are an important food for many other animals. Presence of crayfish in a stream or pond usually indicates good water quality.