Every spring and early summer, something remarkable happens along Connecticut’s shoreline. As the tides rise, thousands of horseshoe crabs emerge under the cover of darkness to continue a ritual that has remained largely unchanged for hundreds of millions of years.
The past two summers, I had the opportunity to volunteer with Project Limulus at Southport Beach CT, helping researchers safely tag horseshoe crabs as part of an ongoing conservation effort. Spending a morning alongside scientists, volunteers, and families gave me an even greater appreciation for these extraordinary animals and the role they play in keeping Long Island Sound healthy.
As a coastal Connecticut Realtor specializing in Fairfield, Southport, and Westport, I believe one of the greatest privileges of living here is being surrounded by an incredible coastal ecosystem. Protecting it helps preserve the quality of life that makes our shoreline communities so special.
Here are ten things you may not know about horseshoe crabs.
1. Despite Their Appearance, They Can’t Bite or Pinch You
Horseshoe crabs often surprise people with their armored shells and long pointed tails. Fortunately, they’re completely harmless to humans.
They have no teeth, no stingers, and no claws capable of pinching. Their tail, called a telson, isn’t a weapon—it’s simply a tool they use to flip themselves over if waves leave them upside down.
2. They’ve Been Around Since Before the Dinosaurs
Horseshoe crabs have survived for more than 445 million years, making them one of Earth’s oldest living species.
They’ve lived through multiple mass extinctions, the age of dinosaurs, and even the Ice Age. Few living creatures can claim such an extraordinary history.
3. The Males Really Do Wear “Boxing Gloves”
One of the easiest ways researchers identify males and females is by looking at their front pincers.
Male horseshoe crabs have distinctive hook-shaped claws that resemble tiny boxing gloves. These specialized claws allow the male to hold onto the female during spawning as she lays eggs along the shoreline.
Once you know what to look for, it’s surprisingly easy to tell them apart.
4. They’re Living Ecosystems
A single horseshoe crab supports an entire community of marine life.
Their shells often become home to algae, barnacles, mussels, slipper shells, and other organisms, creating miniature ecosystems wherever they travel.
In many ways, they’re not just part of the ecosystem—they’re ecosystems themselves.
5. Their Eggs Feed Thousands of Migrating Birds
Each female can lay tens of thousands of eggs during spawning season.
Those nutrient-rich eggs become a vital food source for migrating shorebirds traveling thousands of miles along the Atlantic Flyway. Without healthy horseshoe crab populations, many bird species would struggle to complete their migrations successfully.
Healthy beaches support healthy wildlife.
6. Their Blood Has Saved Countless Human Lives
One of the most remarkable facts about horseshoe crabs is that their blue blood has transformed modern medicine.
Their blood contains specialized cells that clot instantly in the presence of harmful bacterial toxins. Scientists developed a test using this natural reaction that helps ensure vaccines, intravenous medications, implantable medical devices, and many injectable pharmaceuticals are free from dangerous bacterial contamination before reaching patients.
Research involving horseshoe crabs has also contributed to advances in vision science and has inspired innovations used in specialized surgical materials and wound care.
7. Their Eyes Are Unlike Almost Any Other Animal
Horseshoe crabs have multiple eyes positioned around their bodies, each serving different purposes.
Their unique visual system has been studied for decades and has expanded scientists’ understanding of how vision and the nervous system process light and movement—research that has influenced both medicine and neuroscience.
8. Their Population Has Been Declining
Although horseshoe crabs have survived for hundreds of millions of years, modern challenges have put increasing pressure on their populations.
Habitat loss, shoreline development, harvesting, and climate-related changes have all contributed to population declines in parts of their range.
That’s why monitoring and conservation efforts are so important.
9. Project Limulus Has Been Protecting Long Island Sound for Decades
Project Limulus began in 1997 to better understand and conserve horseshoe crab populations throughout Long Island Sound.
Since then, volunteers and researchers have tagged approximately 98,000 horseshoe crabs, collecting valuable information about migration patterns, longevity, spawning behavior, and population trends.
One of the project’s greatest strengths is its commitment to public education. Community volunteers—including local residents like me—work alongside scientists to collect meaningful data while learning firsthand why these remarkable animals matter.
Every tagged horseshoe crab contributes another piece to a much larger puzzle.
The information collected through Project Limulus helps scientists make informed conservation decisions that benefit wildlife, coastal habitats, and ultimately everyone who enjoys Long Island Sound.
Living along Connecticut’s shoreline means being stewards of an extraordinary environment. Whether you’re walking Southport Beach, kayaking in the Sound, or simply enjoying the beauty of our coastline, horseshoe crabs are quietly playing an essential role beneath the surface.
Horseshoe crabs are tagged in NY, CT, MA, and RI. They tend to travel long distances!
If you find a horseshoe crab with a white disc please call 1-888-LIMULUS (1-888-546-8587) to report the tag number, location (specific beach), date you found the crab, and if the crab was alive or dead.
If you see a yellow cinch tags call 203-365-7577 to report the tag number, location (which beach), date you found the crab, and if the crab was alive or dead.
Please return live crabs to the water.
I’m grateful to have participated in this year’s Project Limulus event and look forward to volunteering again. Experiences like these remind me why I’m so passionate about our coastal communities—not only for the beautiful homes they offer, but also for the incredible natural resources that make Fairfield, Southport, and Westport such special places to live.
Have you ever spotted horseshoe crabs along Connecticut’s shoreline? I’d love to hear about your experience—or better yet, consider volunteering at a future Project Limulus event. It’s a memorable way to give back to one of our region’s most remarkable natural treasures.
Luxury Coastal Real Estate Specialist | Fairfield Beach, Southport & Westport CT | Waterfront & Lifestyle Transitions | William Raveis Real Estate
Buying or selling a home can feel overwhelming, or exciting. It is one of life’s biggest transitions — and it often comes with more questions than answers. How do I price my home for top dollar? What upgrades matter most to buyers? How can I compete for Fairfield Beach or Westport CT homes for sale without overpaying?
I’m Linda Raymond, a Fairfield County Realtor with William Raveis, and I'm here to guide you to make informed decisions so your move is smooth, strategic, and successful!
As a lifelong Connecticut resident who has lived and worked in Westport, Fairfield, Southport, and neighboring towns, I bring deep local knowledge and community connections. My clients trust me for personalized service, innovative marketing, and results-driven strategies that help sellers achieve the best price and buyers find the right fit — whether that’s a luxury home in the Fairfield Beach Area or Westport or a first home in a welcoming neighborhood.
With nearly 100 five-star reviews and recognition as a Luxury Property Specialist, Chairman’s Elite Club member, and Connecticut Magazine’s Five-Star Professional Award winner, my track record speaks for itself. But what I value most are the long-term relationships I’ve built. Many of my clients return — or refer friends and family — because they know I’ll put their goals first.
Whether you’re upsizing, downsizing, or relocating to Fairfield County, I’ll start by listening closely to your needs and priorities. Then, I’ll create a custom plan to help you move forward with confidence.
Let’s make your next move rewarding — and even exciting. Call or text me today at 203.912.4440 to connect with a trusted Fairfield and Westport CT Realtor.
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