The blood of a horseshoe crab is blue, a translucent baby blue that looks as precious as it is. The blood contains a mechanism, LAL, that detects pathogens and clots around them; pharmaceutical companies use this substance to screen the drugs they sell. LAL is introduced to the drug, and if the clotting action takes place, technicians know the lot is not pure. On the world market, a quart of horseshoe crab blood is worth an estimated $15,000, leading to annual revenues of $50 million. Each year 250,000 crabs are hauled up from the depths, strapped to steel counters, pierced with thick needles and steadily bled.
Incredibly, most survive the ordeal. The LAL industry reports that the mortality rate is 3%, while independent studies reveal higher numbers: 10 to 30%. Technicians first wash the sand and debris from the creatures, then check for injuries or signs of illness. Those that make the cut lose one third of their blood, which takes about an hour. Within three days these crabs are back in the water, released in areas beyond the harvest zones. Their blood volume rebounds in a week, while their blood cell counts take months to recover. Horseshoe crabs are bled repeatedly, though only once a year according to LAL manufacturers. The impact of the procedure on their behavior and breeding cycles is not clear. We can safely assume it does them no good.
Armored against time, horseshoe crabs have been around for 450 million years and are related not to crabs but to scorpions and spiders. Despite the constant threat of infection by any number of marine-borne fungi, viruses and bacteria, these creatures have survived in great numbers, the LAL in their bodies clearly outstripping the white blood cells we rely on.
Horseshoe crabs have ten walking legs and a total of nine eyes scattered throughout the body, along with several light receptors near the tail. Their bodies are composed of three parts: the head, which includes the brain, mouth, heart and nervous system; the spiny abdomen, which houses the legs and gills; and the sharp but harmless tail. They molt several times, starting out the size of peas and growing up to two feet long—the females are larger than the males. Maximum growth is reached in ten years, with life spans topping out at 20 years. The crabs spend most of their time crawling on the bottom of bays, feeding on worms and mollusks. They swim upside-down.
The mating ritual of the horseshoe crab is another astonishing feature. At high tide in late spring, on the new and full moons, horseshoe crabs travel from deep ocean waters to the beaches they were born on. The male crabs arrive first, and when the females come to shore, the males grasp onto them and together they head to the high tide mark. On the way, the females dig several small nests in the sand and deposit eggs, tens of thousands of them, which the males, dragging behind the females, fertilize. These eggs are a tasty treats for birds, reptiles and fish, and most horseshoe crabs will not even make it to the larval stage before being eaten.
Between habitat loss in coastal Japan and over-harvesting on the Eastern Seaboard, horseshoe crab populations have fallen sharply in recent years. We no longer get insulin from the pancreases of pigs and cattle, and research is underway to create a synthetic version of LAL. With our scientific know-how, our startling medical advances, how far away could we be from a crab-free product? Considering the time and expense involved in harvesting, prepping and bleeding horseshoe crabs, the savings would be tremendous. The benefit to the crabs of course would be incalculable.
Some argue that horseshoe crab bleeding is a sustainable practice and that these creatures have proven themselves hardy. Even if this were the case, and I have my doubts, shouldn’t we want to spare them the trauma?
Along with intellect, humans were given compassion, the capacity for decency. Our brains might solve our problems, but our hearts can save the world.