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CRITTER SPOTLIGHT: White River Crayfish: Procambarus acutus

There are over 500 species of crayfish in North America. Four of these have been identified in Rhode Island waters. The most common is the white river crayfish, Procambarus acutus. White river crayfish range from 6-13 centimeters in length. All crayfish are crustaceans. Crustaceans are arthropods. Arthropods are critters that contain segments that are joined together. Like all macroinvertebrates, crayfish lack an internal skeleton, but they do have exoskeletons. Exoskeletons are hard coverings made of chitin, which is similar to keratin which helps form human fingernails. Crayfish shed their exoskeletons as they grow. They will shed many times as youngsters, progressing to just one or two times a year as they age.

Crayfish are ectothermic which is a more scientific way to say cold-blooded. This means that a crayfish cannot control its body temperature and must use its environment to help. When it is cold, crayfish stay primarily in underground mud burrows where they can stay warm. Crayfish are known to be nocturnal, but it is not uncommon to see crayfish out during the day gathering up the sun.

Crayfish are omnivores and will eat everything from algae to other small invertebrates. Crayfish are also known cannibals and will eat their own kind if other food is unavailable. Crayfish provide food for many animals. Birds, amphibians, reptiles, raccoons, otters, and mink are all predators.

White river crayfish live in a variety of freshwater habitats including swamps, marshes, wetlands, streams, ponds, and rivers. Not all crayfish live in freshwater. There are saltwater and brackish water species of crayfish as well.

Crayfish can tolerate a significant amount of pollution in their watershed but are sensitive to chemicals and metals. Crayfish breathe using gills, so they do require dissolved oxygen, but unlike fish and other gilled invertebrates, they don't require high levels of oxygen and can go some time without it.

A cool fact about a crayfish is that it can swim backward using its tail. Crayfish move very quickly this way, and can abruptly jerk their bodies backward to escape a predator's grasp.

I hope you enjoyed learning a little more about the white river crayfish. If you are interested in learning more about crayfish, a great book to pick up is The Life Cycle of a Crayfish by Bobbie Kalman.

Happy Exploring Watershed Scientists,

Mrs. Morissette

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