You Are What You Eat

People who say this don't mean that if you eat a carrot, you will have carrots growing out of your skin. But the little creatures called nudibranchs seem to have taken the expression seriously. When a nudibranch eats a poisonous sponge or a mouthful of sea anemone stingers, something quite like this does happen. Instead of getting sick or dying, the nudibranch safely stores these poisons in its own body. Then if another animal tries to eat the nudibranch, that animal will get a mouthful of sponge poison or anemone stingers.

Nudibranchs are a type of sea slug. Sea slugs, like slugs on land, are snails without shells. Most sea slugs are tiny—only about one-half inch long—although one species averages a foot in length. Without the protection of a shell, a nudibranch may look like a slowly moving meal to a faster animal. Also, because they can't move very far or fast, nudibranchs must eat whatever is close by. So nature has provided them with a fascinating bag of tricks to help them survive.

Nudibranchs are found in a variety of colors and shapes. The nudibranch (left) shows off its two, long, featherlike attachments that contain chemical sensors, which the animal uses to explore its surroundings.