Nature Conservancy Magazine: Summer 2008 - Jurassic Beach

Beach party: A female horseshoe crab lays about 80,000 eggs each spring. The smaller male crabs line up behind, maneuvering to be the one to fertilize the eggs.

Go Deeper

Sidebar: Delaware's Dinosaur
The American horseshoe crab is an ancient species whose closest relative—the trilobite—died out more than 250 million years ago.

Delaware Bayshores
More than a million migratory shorebirds depend on the horseshoe crabs converging on Delaware beaches each year.

One by One

Back on Big Stone Beach, Conservancy volunteer Lois Davis crouches down to look at a struggling horseshoe crab—one of many along the length of the beach. The crab has been flipped upside down by the waves, and its legs are flailing in the air. Some crabs manage to use their long spiky tail to right themselves, but this one looks stuck. Horseshoes are frequently stranded like this, and many will not survive; one study shows that up to 10 percent of the spawning population dies this way.

“There must have been rough waves earlier today if so many are turned over,” says Davis. She reaches down and, lifting the crab by its shell—the proper technique, she says, rather than grabbing its tail—flips it over. “It’s kind of addictive, turning them over and putting them back in the water,” she says, smiling. “A lot of people like to flip them.” After taking a moment to get its bearings, the crab scuttles back into the bay.

Even if she saves only a few horseshoes tonight, she says, it’s satisfying to help them in such a simple way. It’s the same way she feels about the crab count. As a volunteer for the Conservancy over the past four years, she has helped gather small bits of data for the annual spawning count, hoping it will tally up to something larger.

Davis wanders a bit farther down the beach and flips another crab. Several others sprawl out ahead of her, waiting for rescue. She aims to be back next year.

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