What the Heck is a Horseshoe Crab and How Has it Already Saved Your Life?

Horseshoes prove to be lucky again! Unless you’re a horseshoe crab, that is.

Horseshoe crabs may have “primitive” blood, but advanced medical research couldn’t exist without their primitiveness.According toHuffington Post, “Every drug certified by the FDA as well as every implant and prosthetic device must be tested using an extract from the animal’s milky blue blood.”

Yet, since 2004, the wild population of horseshoe crabs has been on the decline. Scientists already learned that captivity isn’t the be-all end-all solution either. While they aren’t necessarily overfished, their population is definitely vulnerable. And you’ll see how if they’re vulnerable, human health and human lives are definitely vulnerable too.

Whats So Special About Blue Blood?

Unlike humans, horseshoe crabs have a “primitive immune system.” Their blood contains the Limulus Amebocyte Lysate (LAL) compound which helps the crabs fight infections. The LAL compound differs from our compounds by binding and clotting around threatening and invasive agents, e.g. fungi, bad bacteria and viruses.

Without the the horseshoe crab’s LAL compound, the LAL test wouldn’t be possible. The LAL test screens for bacterial contamination. The LAL test can find very minute traces of a contamination — a concentration of one part per trillion. If the compound detects a toxin, then binding and clotting properties kick in and contain it; a gel-like substance will then form for further evaluation.

Cold-Hard Captivity Numbers

Blood from the horseshoe crab is a hot commodity. As reported in Huffington Post, the market for products that went through the LAL test is over $200 million, across the globe. In 2012, over 610,000 “animals were harvested for biomedical purposes.” One quart of the horseshoe crab’s blood can sell for up to $15,ooo.

Not surprisingly, extracting the horseshoe crab blood is a gory process. While horseshoe crabs can be raised in captivity, it isn’t that simple. Ethical issues aside of keeping the crabs in captivity, as to be expected, the quality of the crab’s blood deteriorates in captivity. Researchers solve this issue by catching-bleeding-returning wild horseshoe crabs.

The Not So Lucky Horseshoe Crab

While the crabs live on the seafloor, they mate in shallow waters. It’s the perfect opportunity to capture the wild animals. Once captured, the crabs are shipped to research laboratories, and “the tissue around their hearts is pierced and 30 percent of their blood is drained.” After the blood’s been extracted, the horseshoe crabs are returned to the ocean in order to avoid rebleeding.

Even though the process is not as invasive compared to something like vivisection common practices, it isn’t a completely innocent procedure either; it’s more than crabby crabs. While the crab’s blood volume does bounce back within the week of being returned to the ocean, it can take a few months for the cell count to return. Between 10 and 30 percent of the returned horseshoe crabs will die. Therefore, if you have ever used pharmaceutical drugs, then you probably already have horseshoe crab’s blood on your hands.

The Declining Horseshoe Crab Population

Extracting wild horseshoe crab’s blood has affected the population of the crab. While climate change can also be playing a role, there’s little doubt that human research intervention is another likely culprit. A big red flag is that the animals are obtained during the mating season (which only lasts 4 weeks), and many never actually get to…well, mate.

According to Huffington Post, researchers also found that bled crabs “are more lethargic and less likely to follow tides.” Behavioral changes aren’t even the worst part. The horseshoe crab’s health can drastically be compromised because lower blood levels and cell counts, coupled with unnatural behaviors, can negatively impact the animal’s ability to ward off infections. One research project found that eight percent of the studied returned bled crabs died upon being returned.

A More Humane Way?

As reported in Nature World News, 30 percent of the crab’s blood is taken. That type of blood loss easily disorients the crabs. Researchers suggest trying to wait to the end of the breeding season and creating better transportation modes for the animals to reduce stress. Yeah, transportation is a biggie. Not only are the horseshoe crabs plucked in the peak of their mating prowess, but they are transported “in a state of stress and suffocation” when a water-based transfer would be more humane.

Yet, humans haven’t been the most humane to the horseshoe crabs…well, not in recent history. As reported in The Atlantic, before the crabs were valued for their blue blood and they were exploited in the name of science, humans had steaming and grounding the crabs for fertilizer meal down to a science; we’re talking millions upon millions of harvested horseshoe crabs.

Some throw around the primitiveness card to justify the inhumane treatment of the horseshoe crab. Last I checked, humans have lingerings of a primitive reptilian brain, too. I don’t know about you, but inhumanely exploiting an animal (e.g. is suffocating it on the way to a lab really necessary?) feels more primitive than any blue blood. Especially when that animal has saved billions of human lives.

Photo Credit: Angel Schatz


Jim Ven
Jim Ven3 years ago

thanks for the article.

Jim Ven
Jim Ven3 years ago

thanks for the article.

Carrie-Anne Brown

thanks for sharing :)

Lynn C.
Past Member 4 years ago

Another insanity perpetuated on the animal kingdom by human'kind'. Sickening.

Manuela C.
Manuela C4 years ago

Those poor creatures!

Sue Matheson
Sue Matheson4 years ago


Teresa W.
Teresa W4 years ago

Blue blood? An aristocrat! :-)

vicky T.
vicky T4 years ago

It takes a true psychopath to treat an animal that way. At least make the process more humane!

Marianne C.
Marianne C4 years ago

If there's really no other alternative, at least capture the crabs humanely, transport them in water, and take less blood per individual.

It wouldn't hurt if you also kept them around under observation for a couple of days to be sure they were building back up before just dumping them back into the ocean. And mark their shells in some way so you don't keep pulling the same animals out again. Give them a year to breed between bleedings. They may live for 20, 30, or even up to 40 years if left alone, but when bleeding kills so many, you need to be sure that those who live through the process rebound healthy enough to mate the following year.

It's sheer stupidity to keep risking the loss of the species. Take care of them; we're expecting a lot OF them.

LMj Sunshine
James merritt jr4 years ago

Thank you for article.