The Extraordinary Horseshoe Crab: Long Island’s Ancient Neighbor

If you spend enough time on Long Island’s beaches—especially in late spring—you’ll eventually cross paths with one of our most extraordinary coastal residents: the horseshoe crab. They look prehistoric because they are prehistoric. Horseshoe crabs have been around for roughly 445 million years, quietly surviving mass extinctions, shifting continents, and the rise and fall of entire species. And now, they need our help.

Why Horseshoe Crabs Matter More Than Most People Realize

1. Their Blood Has Saved Countless Lives — And Now We Must Protect Them

Horseshoe crab blood contains Limulus Amebocyte Lysate (LAL), a substance historically used to test medical equipment and vaccines for bacterial contamination. This made horseshoe crabs invaluable to modern medicine.

But here’s the truth: we must move toward alternatives.

When horseshoe crabs are harvested for blood, 10–30% die afterward, and many survivors experience reduced reproduction. Over time, this has contributed to population declines.

Fortunately, synthetic alternatives to LAL now exist and are being used increasingly—safer for wildlife, just as effective for medicine, and a path toward sustainability.

2. They Are Critical to the Atlantic Ecosystem

Horseshoe crab eggs are a vital food source for migratory birds—especially the red knot, which stops in New York during a migration stretching 9,300 miles. A drop in horseshoe crab numbers stresses the entire coastal ecosystem.

3. They Support Local Marine Life

Crabs, turtles, fish, and shorebirds all benefit from the spawning habitat horseshoe crabs create. They are quiet ecosystem engineers—vital, humble, irreplaceable.

How to Safely Help a Horseshoe Crab

Horseshoe crabs often get flipped onto their backs by waves or during spawning.

1. Flip It Gently — Never Use the Tail

Place your hands on the sides of the shell and rotate it like a steering wheel.The tail (the telson) is not a stinger—but it is fragile.

How-to video (Cornell Cooperative Extension):▶️ https://www.youtube.com/watch?v=JxSx4DPF8uM

2. Support the Body If You Must Carry It

Use two hands under the shell. Avoid the tail entirely.

3. Let Them Be When Possible

If the animal is upright and safe, simply admire and keep your distance.

How to Tell a Male vs. Female Horseshoe Crab

If you want to help with monitoring—or just identify what you’ve found—it’s easy:

Male:

• Smaller

• Claspers on front legs resembling tiny boxing gloves

• Often holding onto females during spawning

Female:

• Larger

• No claspers

• Usually the one doing the digging

• 
  

Photo guide:📘 https://www.horseshoecrab.org/act/facts.html

(Scroll to “How to tell male from female.”)

If You See a Tagged Horseshoe Crab

Tags help scientists track population health and movement.

If you see one, you can report it to:🔗 USFWS Horseshoe Crab Tagging Programhttps://www.fws.gov/crabtag/

Or report tags directly through Cornell Cooperative Extension’s Long Island site:

🔗 https://ccesuffolk.org/marine/citizen-science/horseshoe-crab-monitoring

Information to note:

• Tag number

• Date found

• Exact location (GPS is ideal)

• Whether the animal was alive or deceased

• Male or female

Your report directly supports conservation.

Long Island’s Role: A Crucial Stronghold

Long Island is home to some of the most important spawning beaches on the East Coast, including:

• Cupsogue

• Shinnecock Bay

• North Shore coves

• Cedar Beach

• Jamaica Bay

• Peconic Estuary

Protecting these areas protects the population across the entire Atlantic.

Thank You to the Organizations Protecting Horseshoe Crabs

A heartfelt thank-you to the local and regional groups working tirelessly to study and protect horseshoe crabs:

• Cornell Cooperative Extension Marine Programhttps://ccesuffolk.org/marine

• NY State DEChttps://www.dec.ny.gov/animals/37142.html

• Atlantic Marine Conservation Society (AMSEAS)https://www.amseas.org/

• Seatuck Environmental Associationhttps://seatuck.org/

• Peconic Estuary Partnershiphttps://www.peconicestuary.org/

• The Horseshoe Crab Conservation Associationhttps://www.horseshoecrab.org

• Local volunteer monitoring networks across Long Island

  
  

Your late-night beach surveys, data collection, rescues, and public education efforts give this ancient species a fighting chance.

Long Live the Horseshoe Crab

These remarkable creatures have outlived dinosaurs and survived ice ages. Long Island’s beaches are among their last and most important refuges—and with a little knowledge and care, we can help ensure they thrive for generations to come.

The next time you see that helmet-shaped shell emerging from the surf, take a moment to appreciate that you’re looking at one of Earth’s oldest living species—resilient, essential, and worthy of protection.