Photographed by Bette Jackson



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Hi, I'm Dr. Jerry Jackson, out with the wild things. Around Chesapeake Bay, horseshoe crabs come ashore each spring in massive numbers and their eggs are now known to be essential food for a shore bird known as the red knot. The red knot is only a visitor to Chesapeake Bay, stopping there in route from its wintering area in South America to its nesting area on the Artic tundra. As horseshoe crab numbers have declined due to pollution and human exploitation, red knot members have also declined. In Florida, the eggs of horseshoe crabs are also likely an important food for migrant birds and a diversity of other creatures. Although a single female horseshoe crab may lay 90,000 eggs in a season, one estimate suggests that only ten of those will survive to produce an adult horseshoe crab. Nature’s seeming extravagance is matched by the rigors of the world in which the horseshoe crab lives. Horseshoe crabs play important roles in our own world, too. For example, an enzyme in horseshoe crab blood has proven very important to the detection of impurities in medicines that are injected into the human circulatory system.