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Photo of a Rusty Crayfish

Rusty Crayfish

Most Montana kids call them crawdads, but the most common member of the crustacean family in the state is also known as crayfish, mudbug, and crawfish, and almost 400 different species of crayfish are found in North America. The term "cray" in their name may have come from the word crevice, which is a word which means a small space, which is where crayfish like to hide.

Crayfish in Montana live in rivers, lakes, ponds and marshes, just about anywhere there is a permanent source of water. They seem to be especially common in areas of rivers and streams with rocky bottoms. Crayfish love to crawl inside the spaces and crevices between rocks, although they will also lurk under sticks and logs, or even sometimes burrow into the mud.

It's easy to recognize crayfish, just look for those two big pinchers, which they use as tools to help them feed and defend themselves. Most crayfish in Montana grow to about three or four inches long in their two or three year life span. In southern states, crayfish have been known to grow as long as 16 inches!

In their watery homes, crayfish are most active at night, when the venture out of their burrows to feed on snails, algae, insects, worms, and small fish. Not only will crayfish feed on a wide variety of food items, but many other mammals, birds and fish think that crayfish make a wonderful meal. In parts of the United States, there are farms which hatch and grow crayfish, which are then sold to stores and restaurants for people to eat. Crayfish are usually boiled like lobsters, and the meat from inside of their tails can be delicious.

Since they are cold-blooded animals, crayfish become more and more active as the water warms up each spring, and are most active in water temperatures of 50° or more. Throughout the summer, as the crayfish eat and grow larger, they must shed their hard outside skeleton, or exoskeleton. Since they do not have bones, this outside covering protects the crayfish from predators and other crayfish. When they shed their exoskeleton, the new skeleton is quite soft, and the crayfish will hide for a few days until the skeleton becomes harder.

The lifecycle of a crayfish begins in the summer. The female crayfish carries the eggs on the underside of her belly for four to six weeks, until they begin hatching. As the water temperature rises, the young crayfish hatch, although they stay attached to their mothers until they have grown and shed their own exoskeletons a few times. Finally, they are large enough to crawl away and begin life on their own.