It’s one of the very oldest creatures on the planet, believed to have crawled around the oceans’ shallow waters before dinosaurs and flying insects existed. And in spite of its name, it’s an Arthropod and is more closely related to spiders and scorpions than to crabs.
Horseshoe crabs, found along Asian and Atlantic coasts, were once incredibly revered in Japan:
”In ages past brave warriors who honorably sacrificed their lives in battle were said to be reborn as horseshoe crabs, their shells samurai helmets, eternally crossing the bottom of the sea.”
And they’ve given us an astonishing critical ingredient for our medicines:
“The horseshoe crab plays a vital, if little-known, role in the life of anyone who has received an injectable medication. An extract of the horseshoe crab’s blood is used by the pharmaceutical and medical device industries to ensure that their products, e.g., intravenous drugs, vaccines, and medical devices, are free of bacterial contamination. No other test works as easily or reliably for this purpose.”
Like other creatures we’ve featured on Oceanwire (Monk seals and coelacanths), Horseshoe crabs are often referred to as “living fossils”, because they have essentially not changed in millions of years. The earth has changed around them, though, and like so many creatures that have survived epochs humans couldn’t survive, they now face threats, primarily stemming from humans, that may soon make them disappear.
In Asia, they can be a source of income. Enterprising film producers at Riverbank Studios in New Delhi made the film excerpted below, and helped spur the Indian government to list Horseshoe crabs for protection under the country’s Wildlife Act (check out the stunning opening footage of embryo):
How can you make a difference for Horseshoe crabs? Learn about them – here’s great info from NOAA’s SeaGrant. Help crowdsource info about them at iNaturalist. Spread the word about how remarkable and irreplaceable they are. ERDG has plenty of actions you can take – including the simple and effective “Just Flip ‘Em” program. And, like everything in our oceans and along our coasts and rivers leading to the oceans, support ocean conservation and research every way you can!
Great read – Spring Fling: Prehistoric horseshoe crabs spawn on moonlit beach, WashPost
Hat tip to Beach Chair Scientist for sparking our imagination on this post!