Ask a Lifeguard -- What's with the horseshoe crabs?

Date Published: 
June 15, 2012

We see them washing up on our guarded beaches, floating like heads out in the Atlantic, or in broken pieces scattered along the tideline. What’s the situation for these horseshoe crabs? Why don’t we see this happening to other sealife?

Coastal Point • Stock photographyCoastal Point • Stock photography

May and June are the prime spawning months for the horseshoe crabs. During the full and new moons of these months, horseshoe crabs take advantage of the higher tides. But as they get ready for these tides, the horseshoe crabs congregate in the shallow water just beyond the ocean’s waves and along the nearshore areas of the inland bays.

When the time is right, the females come on shore to “nest,” forming a shallow depression in the sand and depositing their eggs. The males come right along — sometimes hitching a ride on the backs of females — to fertilize the eggs.

Unfortunately, this mating ritual puts the horseshoe crabs into harm’s way in the ocean. The shallow water is the area most impacted by waves. Gentle waves can help bring the horseshoe crabs to shore. But powerful waves can kill them, smashing them in the impact zone.

If a large adult horseshoe crab makes it to shore alive, it’s probably out of the ocean on purpose. After all, these creatures are estimated to be at least 300 million years old and predate dinosaurs, according to the Web site of the University of Delaware’s College of Marine and Earth Studies (

So let the horseshoe crab do what it came ashore to do.

However, if you see a horseshoe crab out in the water beyond the waves floating and bobbing “like a severed head,” as some beach patrons describe it, leave it alone, too. It’s dead. And, no, we lifeguards are not going to go rescue it.

Some people want to get involved watching the mating ritual and spending time with the horseshoe crabs. Volunteers can join the Center for the Inland Bays for their 2012 Horseshoe Crab Survey. Beware — you’ll need to be a night owl for this! There are several nearby bayside locations, such as James Farm Ecological Preserve, Holts Landing and Bay Colony, where volunteers meet to watch and record the horseshoe crabs in action. Check out for more information.

Horseshoe crab fans, check out This group sells stickers and shirts featuring this unique creature and donates funds from the sales to local habitat preservation efforts.

Long live horseshoe crabs! If you step on a slightly slimy, hard, helmet-shaped thing while in the water, don’t worry. The horseshoe crabs under us are pretty tough. They’ve been around this long, and they’ll be here long after we’ve gone.

Dana Schaefer has been a local ocean rescue lifeguard for 15 years. Do you have a question for a lifeguard? Ask her at