Ancient Mariner

A horseshoe crab (Limulus polyphemus) swims in the shallows off Monomoy Island. Click on the photo for a better view of the seaweed and mollusk beard on his shell.

"IT is an ancient Mariner,
And he stoppeth one of three.
By thy long beard and glittering eye,

Now wherefore stopp'st thou me?"

~from The Rime of the Ancient Mariner

By Samuel Taylor Coleridge (1772-1834)
English Romantic lyrical poet, critic, and philosopher

More from my trip to Monomoy National Wildlife Refuge (see previous post):

I encountered this fellow as I was making my way from the beach on North Monomoy Island back to our boat. The horseshoe crab is a distant relative of the spider and is probably descended from the ancient order Eurypterida. Horseshoe crabs are among the world's oldest and most fascinating creatures and are estimated to be at least 300 million years old.

For many decades, humans have harvested the horseshoe crab for use as fishing bait. Since the 1970s, horseshoe crab blood has also been used for medical purposes to the point where their kind have declined significantly, and so have their egg numbers.

Their decline is especially important to the red knot, a small shorebird that is a global traveler of the most impressive kind. The red knot makes one of the longest migrations of any animal — a journey that takes it from one end of the earth to the other. To accomplish this feat, it relies on the eggs of the horseshoe crab. Without these eggs, the red knot is doomed.

To learn more view Crash: A Tale of Two Species, from NATURE.

Horseshoe Crab Information Source: Crash: A Tale of Two Species