Narrator: As the waters warm and tides grow high, horseshoe crabs leave the ocean floor and make their way to the shores and estuaries of the Atlantic Coast. Here in the sheltered waters of South Carolina, they suddenly emerge by the thousands in a spawning ritual they’ve performed for hundreds of millions of years.

On the highest tides, they drag themselves to shore to lay their eggs.

Crabs don’t mature until they’re nine or ten. By then they’ve molted for the last time and their permanent shells can host an ecosystem of hitchhikers.

Horseshoe crabs are safest on the ocean floor. But the only way to carry on the species is to take a risk.

Jerry Gault: We say the ones that see us coming and turn and take off to the water, we caught him before. He knows us. You know?

Narrator: Jerry Gault and his father Bob have worked these waters for decades.

Jerry Gault: We work the moons. The horseshoe crabs come up and spawn on the moons in the springtime.

Bob Gault: If you actually get into the water, you can feel them swimming and sometimes you can’t even catch them because they’ll get to swimming so fast.

Bob Gault: A lot of people seem to be scared when they first see them on the beaches and when they first see them, they do look a little scary, but what I do is put them right up against my face and as you can see, they do not hurt, their pincers are all very light. These are harmless. I just like ‘em.

Jerry Gault: Mine is bigger.

Bob Gault: Mine is younger.

Narrator: For 15 years, South Carolina has banned collecting horseshoe crabs for fishing bait. Now only fishermen with special licenses are allowed to gather crabs for biomedical use – and only if they return the crabs alive.

Few of us realize just how valuable the horseshoe crab is…

Bob Gault: When I first started 37 years ago, we were allowed to harvest them. There was no recording. There was nothing and they Bob became fair game and I was involved with selling them for bait and then a doctor came down and he said that if I didn’t sell bait crabs anymore he would be interested in the laboratory.

Jerry Gault: Normal fishing is you catch it, you ice it, and you deliver it to the table and you eat it. The horseshoe crab we actually catch them, take them to the lab, and they bleed them, and we bring it back and release them, so we’re borrowing the crabs is really what we’re doing.

What do you say we go unload this?

Bob Gault: Alright.

Narrator: Crabs that are “borrowed” end up a couple of hours away at the Endosafe Laboratories in Charleston.

Here in this alien world, they’re given a rigorous cleaning, to prep them for process ahead.

For the past thirty years, the biomedical industry has been mining the medical equivalent of gold.

Endosafe is one of only four labs in the world that produces a derivative of horseshoe crab blood.

Their blood has a clotting agent that’s used to detect minute levels of bacteria.

But what’s truly surprising is the color. The crab’s blue blood is an evolutionary gift that’s helped them survive the eons.

Lab Tech: Male or female?

Norman Wainwright : A small male would be good.

Narrator: Dr. Norman Wainwright has been working with horseshoe crabs for most of his career, studying the remarkable properties of their blood.

Norman Wainwright: The beautiful blue color is a result of its blood containing copper as an oxygen carrying pigment instead of hemoglobin, which contains iron. I’m adding a suspension of e-coli bacteria.

At the first sign of bacteria, the crab’s blood forms a protective clot.

Norman Wainwright: Look at that. This is perfect. This is the horseshoe crab cells protecting the animal from infection. Any type of leakage of seawater into their blood system would trigger this response, seal the wound and there actually are proteins in the clot itself that kill the bacteria. They are almost primitive antibiotics.

The phenomenon caught the attention of biomedical companies in the 70’s. They’ve been putting it to work for us ever since.

Up to 1/3 of the crab’s blood is removed during the process – yet most of them survive.

One quart of horseshoe crab blood is worth about $15,000. It’s a multi-million dollar industry.

The clotting agent, called Lysate, is used to test intravenous drugs for bacteria. No IV drug reaches the market without being tested on horseshoe crab blood. It’s an FDA regulation.

Years ago, the only way to screen for toxins dangerous to humans was to use live rabbits. Feverish bunnies revealed contamination -- and the test was slow.

Horseshoe crab blood takes an hour tops, and most of the crabs survive the process.

Scientists are exploring alternatives that would make bleeding crabs unnecessary. But each day we’re finding more ways the horseshoe crab can help us -- with everything from sutures to contact lenses.

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