Teacher Resources

Imagine if the next time you go swimming, you could swim right by a spider's relative. Up to three feet long, shaped like a brown armor plated tank trailing a spiky pointed tail. Horseshoe crabs have existed on earth unchanged for twice as long as the dinosaurs lived.

If you were a fisherman you might chop the horseshoe crab up into little pieces to use as bait to catch conch and eels. This isn't really a good idea, though. For so many horseshoe crabs have harvested that their population is dwindling. Some areas in New England have even stopped horseshoe crab fishing altogether to try to help the population recover.

If you were a doctor, you'd want your crabs alive. The 1967 Nobel Prize in Medicine was awarded for research on vision and eyes using Horseshoe crabs. If you had a bad burn, you would wish for horseshoe crab chitin, a chemical used in making bandages that helps burns heal up to 50% better than just ordinary bandages. All of us have been helped by the bright blue blood of the horseshoe crab. Several companies harvest blood from horseshoe crabs - sort of like a marine blood donor program. They use the blood for its special chemical called LAL. This chemical, only found in horseshoe crabs, can test injectable medicine (such as vaccines and IV fluids) to make sure they are safe and bacteria-free before they are used on people. This chemical is also used to test artificial limbs and pacemakers - just about anything that would be put inside your body. Aren't you glad that the horseshoe crabs are around to make sure that these things are safe? Most companies that harvest the crabs for their blood return them to the wild to continue a normal crabby life.

Horseshoe crabs live in legend, too. The Japanese call horseshoe crabs Kabutogami. Brave warriors who died honorably in battle were said to be reborn as horseshoe crabs. Their shells mimick the shape of a samuri's helmet.