CRITTER SPOTLIGHT: The Crayfish
Good Morning Watershed Explorers,
Crayfish have many names, they can be called crawdads, mudbugs, spoondogs, crawfish, yabbies and more. However, no matter what you call them, crayfish are crustaceans. A crustacean is an arthropod or an animal that is made up of many segments. As you all know from our lessons together, crayfish are macro invertebrates. This means they have no bones. They have an exoskeleton that protects their body. Exoskeletons are made up of a material called chitin which is similar to the material that your fingernails are made of. Crayfish molt their exoskeleton six to ten times in their first year of life. This will decrease as crayfish age, but if they are growing, they are molting.
Crayfish have a very intricate life cycle. I have attached a picture below so that you can see the stages. This picture comes from a book entitled The Life Cycle of a Crayfish.
There are over 540 species of crayfish in the world and of those 540, about 350 species are found in North America. Depending on the species and size of the crayfish, they can live from 2-20 years. The oldest known crayfish lived to 30 years. Different species can be different colors. There are blue and pink crayfish and some that are even white. Most crayfish here in Rhode Island are red and brown. A little known fact about crayfish is that they camouflage to their surroundings. This happens as they molt. If a crayfish has a lot of algae in its environment it may actually start to take on a greenish color.
Crayfish can be found on every continent except for Africa and Antarctica. Apparently Africa is too hot and Antarctica is too cold! Crayfish are freshwater critters and enjoy a variety of habitats, from fast moving, cold rivers to slower moving and even warmer ponds and streams.
Most crayfish come out at night, which means, you guessed it, they are nocturnal. They are omnivores eating a variety of plant and animal matter. They are also scavengers and will cannibalize (eat their own kind) if nothing else is available. Crayfish are also food for many creatures. Otters, birds, fish, raccoons, frogs and others will gladly feast on crayfish for a snack. Humans will also consume crayfish in certain areas of the world, although here in Rhode Island a crayfish would be barely a snack as they don't grow much larger than about half a pencil length.
I know some of you are studying the crayfish at home, so if you have any questions about this fantastic creature that you would like to ask, please click the email Mrs. Morissette button and send me and email. I would be happy to hear from you and answer your questions.
This is a crayfish that we found last year at Slater Park Pond. Look at all those eggs!