Doggy Bag - Imagination Cafe

A Crustacean Houdini

Houdini was the greatest magician of his time. One of his most famous tricks was to break free of his chains. Like Houdini, the crayfish breaks out of its shell. Put Houdini in a straightjacket and he would wiggle out. Catch a crayfish by its leg and it will wiggle away, leaving the leg behind. In fact, it grows a new leg!

Houdini's real name was Ehrich Weisz. The crayfish, too, goes by more than one name – crawfish, mudbug, and crawdad. Call it what you will, this little creature has magic.

Molting: The crayfish begins its escape act early in life. Crayfish, like other crustaceans, have an exoskeleton that is made of non-living material. The creature inside, however, keeps growing till the shell becomes too tight. This is when the crayfish starts its Houdini act.

It's well known that before allowing himself to be tied up Houdini would breathe in deeply to enlarge the chest cavity and create some wiggle room. The crayfish knows that trick! It puffs itself up, flips over on its back, and waves its appendages in the air to get more oxygen. Soon the shell splits and the crayfish breaks out. At this time a soft and flexible shell that allows growth covers it. This process of growth and molting slows as the crayfish grows older.

Survival Skills: Is breaking out of the shell the crayfish's only escape act? No. It can also escape its watery environment. Though not an amphibian like a frog, the crayfish can survive on land too, because it breathes through a set of gills. As long as the gills are moist the crayfish can stay out of the water. To move around on land it has eight walking legs, attached to the front part of its body.

How did it see that? Some say that Houdini had eyes in the back of his head. Likewise, the crayfish has 360-degree vision. Its eyes are mounted on short stalks that can swivel around. Each eye is composed of many hundreds of light sensitive structures, angled slightly differently like a many-faceted diamond

Special Adaptations: Its long antennae can project in all directions. They act as feelers, providing it with a sense of touch. The shorter ones help the crayfish to smell and taste chemicals. Plus, small hairs provide it with a sense of balance and gravity, so it knows up from down. These adaptations constantly supply the crayfish with information about prey and predators. Like Houdini the master magician, the crayfish is a master of its environment.

Crayfish As Pets

Crayfish are easy to take care of and make great pets at home or in a classroom.

Where to find them:

400 known species of crayfish are found in North America, mostly east of the Rockies and in the southeastern states.
Streams, rivers and lakes are good places to look for them.

How to collect them:

Buy them from a pet store or a biological supply store.
Crayfish hide under rocks or twigs. You can trap them, net them, or pick them up. They pinch hard, so pick them carefully by their shell from behind the pincers.

Care and feeding:

Crayfish hate to be crowded. Put one to a 10-gallon tank. Don't put other fish in the same tank.
Remember to put a filter. Cover the top completely so they can't escape.
Crayfish love to hide. Put rocks, driftwood or pipes in the tank, to give them hiding places.
Change a quarter of the tank's water once a month, more often if necessary.
Crayfish are not picky. They will eat worms, krill, plants, even table scrap, but food that sinks to the bottom is best because they are bottom feeders.
Leave the molt (the shed shell) in the tank. It provides them necessary minerals and calcium.
Do not worry if the crayfish does not eat every day. It will not stay hungry.

Sending crayfish home:

If the crayfish has to be released and you caught it in a local pond or river try to return it to the same place
If it was purchased please return it to the store where you bought it. In the local water it would be an alien, and could cause harm to the plants and fish.

Back to Creature Features