Littering bay shores in summer, the dry, rotted corpses stand like sunburned tombstones. Seagulls pick at the overturned shells, ripping out gills with ruthless abandon. Pier fishermen scowl as they snag yet another reeking specimen. I speak of horseshoe crabs, crustaceans descended from the ancient Trilobite (an extinct arthropod from the Paleozoic era) and one of the best known "living fossils." Common sights for Delaware natives, horseshoe crabs are part of our local landscape and objects of fascination for children and grandchildren. However, there is an uncommon story of 360 million years of survival behind these creatures, and a purpose for their existence besides amusing children and frustrating fishermen.

The horseshoe crab's copper-based blood is vital for detecting bacteria in antibiotics. Limulus Amebocyte Lysate (LAL), a product made from the blood, is used to detect the presence of endotoxin, a substance fatal to humans. LAL is also useful in detecting cancer cells, due to endotoxins inhibiting their growth. Horseshoe crab blood also plays a role in the treatment of meningitis. Caused by a bacterial infection, meningitis is a cold-edged killer, deadly unless treated quickly by antiobotics. When a stricken victim is treated, it's a safe bet that the farthest thing from their mind is the role played by the humble, ancient creature that just saved their life. The horseshoe crab is indeed the source of the cure for meningitis. In its blood flows life for those infected by disease. Much care needs to be taken to safeguard the integrity of the crab's blood when it is processed. To obtain its blood, a needle is inserted into the hinge between the crab's two exoskeleton sections. Any exposure air turns the blue blood a straw color, effectively corrupting it and spoiling it for medical use. Currently, a method is being developed for synthetically creating the life-saving element in the crab blood, so that it won't be necessary to kill crabs to obtain it.

Not only is the horseshoe crab the salvation of those who are infected with meningitis, but it also supports migratory shorebirds on their long journey to their Canadian breeding grounds. The Delaware Bay area is the second largest staging ground for these birds, a vital mid-point pit stop during the time between mid-May and June; the peak in the horseshoe crab's mating season. The migrating shorebirds feast on horseshoe crab eggs. Although at first it may seem barbaric, in many ways this behavior represents Charles Darwin at his best. The birds have no concern for the survival of the horseshoe crab; they gorge on the crab eggs to increase their body weight several times over and replenish their body fat in order to survive the long journey ahead. The horseshoe crab, in an inspiring display of evolution and rugged survival, lays enough eggs to compensate for this loss. Females can produce up to 88,000 eggs per year.

Besides feeding shorebirds, the horseshoe crab is a significant source of food for juvenile Atlantic loggerhead turtles, a threatened species that uses the Chesapeake Bay for its breeding ground.

Rising polution levels and commercial fishing practices have put a dent in the crab population. The long term impact of a declining crab population on bird life and the environment becomes more meaningful when one considers that it takes the horseshoe crab between nine and ten years to mature and reach breeding capability. The damage caused by a decimated horseshoe crab population might drive some species of shorebirds to extinction. Thankfully, the initiative has been taken to preserve this precious species. Treaties and alliances between Chesapeake and Delaware Bay states have been formed to ensure the proper treatment of the crabs. Plans are in motion to declare the Delaware Bay as an official sanctuary for the crabs.

During winter, horseshoe crabs travel out as far as the continental shelf where they burrow and hibernate, leaving them slightly vulnerable to predators. As water temperatures rise in the spring, adults will migrate to the local beaches for spawning. The breeding behavior of horseshoe crabs, that approach the beaches at spring tide to lay their eggs in the sand, is a familiar sight to inhabitants of our area. It is ironic how this survivalist species is one of the clumsiest organisms on earth. It can neither crawl nor swim fast enough to avoid predators, and primitive eyes restrict its detection ability. It cannot burrow fast enough to hide effectively, and its exoskeleton is scarcely hard enough to withstand the probing five-year-old's stick. The crabs' tails, or telsons, are useless for defense and only sufficient for maneuvering. They fail to aid the unfortunate arthropod when it finds itself on its back, vulnerable to the nearest hungry gull.

This brings to mind a well-know story of a man who strolled along a beach and observed someone in the distance bending down, picking something up, and throwing it into the ocean. As he got closer, he saw that a recent storm had washed hundreds of starfish onto the beach where they lay dying. The man saw that a child was picking up starfish one by one and throwing them back into the ocean. After watching for awhile, the man commented, "There are so many starfish on this beach it's not possible for you to save them all. You can't possibly make a difference." Smiling while continuing to toss starfish into the ocean, the child said, "I made a difference to that one."

Think of this little story the next time you see a horseshoe crab struggling to right itself. Give it a helping hand as a way of saying "Thank you" to an ancient friend who contributes so much to our environment and our health.