rayfish by John Cancalosi 1156x650

Crusty Crayfish

By Kathy Kranking

It looks like a lobster, but it’s not a lobster. And it has fish in its name, but it’s not a fish, either. So what exactly is a crayfish?

Crusty Crayfish JJ 2018 RR-1

With claws raised high, the red swamp crayfish above is telling you to BACK OFF! Tiny but tough, crayfish are cousins to lobsters, shrimps, and crabs. Crayfish and their cousins are all crustaceans (kruh-STAYshuns), animals whose bodies are covered with hard, crusty shells. Crayfish are also called crawfish, crawdads, crawcrabs, mudbugs, and other nicknames.

Most crustaceans live in the ocean. But crayfish live in or near freshwater places such as lakes, swamps, and streams. Crayfish need to stay near water because they breathe with gills. They use the gills to take in oxygen that is dissolved in water. As long as its gills stay wet, a crayfish can breathe. If the gills start to dry out, the crayfish must return to water to wet them again. Believe it or not, there are more than 600 species of crayfish. More than half of them live in the United States. And every year, scientists discover more!


If you’ve never seen a crayfish, it might be because crayfish don’t really like to be seen. They’re often most active at night, staying hidden under rocks or logs during the day.

But maybe you’ve seen the mud “chimneys” that top the burrows that some crayfish species build. These crayfish use their claws to dig their burrows. As they dig, they pile up lumps of mud around the entrance. These form the chimneys, which the crayfish crawl through to enter  and leave the burrow. If you ever see one of these chimneys, you know a crayfish is nearby!

When a crayfish isn’t hiding in a burrow or under a rock, it’s usually spending time looking for food. A crayfish has two long antennas (an-TEN-uz), or feelers, and two short ones. Hairs along the antennas and also along the crayfish’s claws help the crayfish feel, taste, and smell. And at the base of each short antenna is an opening that’s lined with hairs. These hairs help the crayfish sense movements in the water.

The crayfish uses all these senses to help it find food. It’s not a picky eater and gobbles up whatever it can find—dead or alive. It will eat  plants, insects, frogs, small fish, and even other crayfish! A crayfish uses its claws to grab food and grip it as it eats.

Of course, lots of animals like to eat crayfish, too. Foxes, raccoons, muskrats, turtles, snakes, birds, and even people will make a meal of these crusty creatures.

After crayfish mate, the female carries her eggs tucked under her tail. The eggs hatch a few weeks later. A baby crayfish looks like a mini-model of its parents. Babies stay with their mother for a while, and she protects them from predators. Eventually each baby will crawl off to live on its own, eating tiny bits of food it finds.

Just like its parents, a baby crayfish is covered with a hard shell. The baby grows inside its shell until it can’t grow any more. That’s when it’s  time to molt, or shed the shell. The shell splits, and the young crayfish climbs out of it. The molted shell looks kind of like a “crayfish suit.”

The crayfish may eat the old shell, which gives it calcium to grow a new shell that will be strong and hard. It can take days until a crayfish’s new, bigger shell hardens. Until then, the crayfish is soft and easier for enemies to attack. So, during this time, it usually stays hidden to  better protect itself. Baby crayfish grow so fast that they may molt every day at first. Later, weeks may go by between molts. After molting  several times, a crayfish will be an adult, living its life the crusty, crayfish way!

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