What is the history of the horseshoe crab?
The horseshoe crab, alias the king crab, alias old horse foot enjoys life along the shallow shores of the western Atlantic and his several cousins live along the shores of the western Pacific and off the coast of China and southern Japan. His life history is a simple story which begins on the sand of his native beaches and ends in the salty water a few feet away, His family history is one of the most fabulous in the entire animal kingdom for he is the sole survivor of a race which otherwise became extinct before the dinosaurs appeared.
He is called a horseshoe or old horsefoot because his crusty shell is shaped like an oversized horse’s hoof. He is called a crab because he lives under a crusty dome and skuttles along on crabby claws. He is called a king crab because he may be more than two feet wide, which is king sized for a crab. All these names, however, are misleading, for he is not a crab at all. He is not even a member of the class Crustacea, which includes most shellfish.
The horseshoe shell is in two parts, with the wide end covering the head and thorax. The tapering tail end of the shell is rimmed with spikes and ends in a spiky tail, maybe two feet long. If you turn him over, you will see what looks like a lurking, king sized spider. Actually, science classes him with the spiders and scorpions, though he is not directly related to them.
The family history of the horseshoe crab began before any living thing existed upon the dry land. Life began in the ancient seas and some 500 million years ago the most important animals in the world were crusty little creatures which have been named the trilobites. Through millions of years, these pioneers changed and adapted in coping with the changing world.
But in time, other creatures developed ahead of them and before life was established on the dry land, the last of the true trilobites had disappeared.
Most experts, however, agree that one descendant of the ancient trilobites had changed enough to cope with the new world teeming with enemies. This fellow was the ancestor of the sturdy horseshoe crab. Now he too is becoming scarce and someday may pass into extinction. Along the Atlantic he is hunted for chicken and pig food and made into fertilizer for the soil. Along the Pacific he is hunted for human food. And the big, sluggish fellow is pitifully easy to catch. For he can be clearly seen along with his friends in a few feet of water where he spends his time grubbing for food on the bottom.
The horseshoe crab tales oxygen through six pairs of gills, but the mother makes one journey in early summer up onto the sandy beach. There she lays her eggs to be washed and wetted by the high summer tides. The youngsters hatch into midget copies of their parents, though they do not grow their long, spiky tails until later.