Crayfish

Cambarus genus

(assorted species: Cambarus robustus, Cambarus bartonii bartonii, Cambarus acuminatus, Cambarus diogenes diogenes)

Copyright, Keith Crandall

Copyright, Keith Crandall

Crayfish can be found in just about any body of fresh water which isn't overpolluted. This includes streams, rivers, lakes, ponds, and sometimes even water-filled ditches.

Crayfish are very common in Northern Virginia, but they are difficult to identify. There are three common genera: Cambarus, Orconectes, and Fallicambarus. Most of our crayfish are Cambarus.

Crayfish can usually be found by turning over rocks in small streams and creeks; the larger the rock, the larger the crayfish. Crayfish are nocturnal, so they do most of their hunting at night.

Copyright, Keith Crandall

Copyright, John White

Crayfish are Crustaceans, and are closely related to lobsters, crabs, and shrimp. They have ten legs; the front two have developed large claws called "Chellae." Be careful! Crayfish are easy to catch, but a large one can pinch hard. Crayfish use their chellae not only to defend themselves, but also to attack prey, move small objects such as stones, and to pick things up.

After crayfish mate, the female carries a cluster of eggs attached to her swimmerets. Swimmerets are the feathery things under the crayfish's abdomen. After the baby crayfish hatch, they will stay on their mother's body for protection until they are big enough to be on their own.

Crayfish are omnivorous, so they eat both plants and animals. They are also scavengers and will eat dead things, as long as they are relatively fresh. Some favorite foods of crayfish are worms, insects, insect larvae, and the eggs of fish, frogs, toads, and salamanders.

Crayfish will create a home for themselves under a rock or a bank by moving smaller items around. They are agressive and defend their territories. Larger crayfish dominate smaller crayfish. How big they get, and how fast they grow, depends on many factors, such as water quality, temperature, and how much food is available. When a crayfish is threatened, it will escape by flipping its abdomen and swimming backwards.

Crayfish have many predators, including raccoons, opossums, snakes, and muskrats.

Additional Media

Description
Type
Credit
Crayfish Preying on Clouded Sulphur
Video
Mark Moran
Crayfish Face Up Close
Video (Very long download, approx. 3 minutes on T1)
Mark Moran
Link to Printable Page
EnchantedLearning.com
Download Quicktime if you are unable to play video.

Relationships in Nature:

PREY/FOOD
PREDATORS
SHELTER
OTHER

Eastern Dobsonfly

Raccoon

Common Duckweed

Copepod SP

Earthworm

Virginia Opossum

Common Cattail

Spotted Salamander

Muskrat

Yellow Pond Lily

Bullfrog

Red Fox

Pickerelweed

American Toad

Barred Owl

Common Reed

Wood Frog

Red-tailed Hawk

Green Algae

Spring Peeper

Largemouth Bass

Lizard's Tail

Green Darner

Channel Catfish

Long-leaf Pondweed

Clouded Sulphur

Bluegill

Hydrilla

Bluegill

Belted Kingfisher

Greater Bladderwort

Largemouth Bass

Yellow Perch

Arrow Arum

Channel Catfish

Common Crow

Swamp Rose Mallow

Yellow Perch

Eastern Newt

Wild Rice

Yellow Pond Lily

Tesselated Darter

Common Duckweed

Crayfish

Common Cattail

Golden Shiner

Freshwater Leech

Eastern Painted Turtle

Crane Fly

Spotted Salamander

Green Algae

Northern Water Snake

Flatworm

Northern Hog Sucker

Relationship to Humans:

Crayfish are a popular animal for children to catch, and often the first "dangerous" animal they come into contact with. Only very large crayfish can do any damage, but even a smaller crayfish's pinch can hurt, so kids learn how to be careful picking them up.

Many people eat crayfish. They are also used by fisherman as bait.

Crayfish help humans in other ways, such as cleaning up dead animal and plant matter from the bottom of streams, and by controlling populations of insects and other animals.

SCIENTIFIC CLASSIFICATION

KINGDOM
Animal
PHYLUM
Arthropods
CLASS
Crustacean
ORDER
Decapods
FAMILY
Cambaridae
GENUS
Cambarus
SPECIES
See species above

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