Six Reasons Horseshoe Crabs are Better Lovers than You

By Emily DeLanzo, Park Ranger at Merritt Island National Wildlife Refuge

Mating horseshoe crabs by Gregory Breese/USFWS

Gadgets and gizmos a plenty — at least in terms of evolutionary adaptations and behavior — horseshoe crabs often scutter their way onto shores up and down the Atlantic Coast and into our hearts. The Atlantic horseshoe crab, one of four species of these special marine arthropods, play a vital role in ecosystems along the eastern coastline of the United States and in several National Wildlife Refuges.

Although horseshoe crabs live most of their lives unseen deep underwater, these creatures emerge in droves during full and new moons on shorelines in states like Florida and Delaware for mating season to lay hundreds of thousands of eggs to ensure this long-lasting species’ existence for future generations.

It’s no surprise that through millennia of survival horseshoe crabs have perfected partnership so here’s six reasons why horseshoe crabs may not slide into your DMs but right into your heart and be better lovers than you.

Horseshoe Crab by Emily DeLanzo/USFWS

1. Horseshoe Crabs are some of the longest living, and in turn most experienced, species on this planet.

Often called “living fossils,” horseshoe crab ancestors can traced back through the geologic record to around 445 million years ago, 200 million years before dinosaurs existed.

2. Horseshoe Crabs have 10 eyes so they see ~*EvErYtHiNg~*~

Despite their hard and tank-like exterior, horseshoe crabs are extremely sensitive creatures, at least towards stimuli like light. These marine arthropods have ten eyes — a pair of compound eyes on their front shell and “photoreceptors” in other areas, primarily along the tail…so you know what that means.

Volunteer Steve Dunn/USFWS

3. Not only do they have 10 eyes, but they have 10 legs to handle you best.

Horseshoe crabs are actually not true crabs at all, being more closely related to arachnids (a group that includes spiders and scorpions) than to crustaceans (a group that includes true crabs, lobsters, and shrimp).

Volunteer Steve Dunn/USFWS

4. Their Get-Togethers are infamous.

During early summer months, horseshoe crabs come to shore by the droves to bump and grind their way into securing the good of their species for future generations through massive orgies.

Emily DeLanzo and Horseshoe Crabs by Charlie DeVoe/USFWS

5. They have WAY more children. Like overwhelmingly so.

During spawning, the female crab partially buries herself in the sand while she deposits a cluster of about 4,000 tiny green eggs. In an evening of egg laying, a female crab can lay several egg clusters, and she may spawn repeatedly over several nights to lay 100,000 or more eggs.

6. Horseshoe Crabs are very, very……patient.

During mating season, male horseshoe crabs will wait near beaches for their ladies. Once united, the smaller male crab attaches himself to the top of the larger female’s shell by using his specialized front claws, and together they crawl to the beach. Nicholas Sparks couldn’t write a more romantic ending.

Can’t get enough of Horseshoe Crabs? Neither can shorebirds!

In addition to the horseshoe crabs at Merritt Island National Wildlife Refuge, there are horseshoe crab populations up and down the coast. The largest population of horseshoe crabs in the world is found in Delaware Bay.

During the spawning season, many eggs are exposed to the beach surface by wave action and the digging action of mating crabs. Once an egg is exposed to air, it can dry out quickly, preventing it from hatching; however, it still plays a vital role in the ecosystem. These exposed eggs are the primary food source for migrating shorebirds making the journey from South America to the Arctic along the Atlantic Flyway.

Photo: Gregory Breese/USFWS
Photo: Gregory Breese/USFWS



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U.S. Fish and Wildlife Service

We’re dedicated to the conservation, protection and enhancement of fish, wildlife and plants, and their habitats.