Horseshoe Crabs

Horseshoe CrabDid you know?

  • Horseshoe crabs are among the world's oldest creatures (300 million years old!)
  • Horseshoe crabs are most closely related to spiders and scorpions
  • Horseshoe crabs eat clams and worms
  • Female horseshoe crabs come out of the water to lay their eggs on the beach.  You may come across nesting females, often with male crabs clinging onto their backs, in the late spring.  The Fish and Wildlife Research Institute in Florida is studying horseshoe crab populations and asks you to report sightings of mating and nesting activity at their website.
  • Horseshoe crabs have been used to study human biology, especially the ways that our eyes work.  Compounds from the horseshoe crab's shell are used to make surgical sutures.  Chemicals from the crab's blood are used in many drugs.
  • The horseshoe crab's tail isn't a weapon--it is used to help the crab flip itself over if it is rolled onto its back.

More Information

Delaware Sea Grant has produced a horseshoe crab model which can be ordered from their website.  The model includes facts about the horseshoe crab as well as a crossword puzzle.  It is recommended for students in grades 5-8.

The University of Florida has a downloadable brochure about horseshoe crabs.  You can access it here.  Note that this should be printed on legal size (8½" x 14") paper.