The horseshoe crab, a crustacean that resembles an armored vehicle patrolling the beach, is one of the most useful creatures in the sea — a trait that could doom it to extinction.

Humans use the horseshoe crabs not only for fishing bait but also for its blood; the crab’s blood contains a compound called LAL, or Limulus Amebocyte Lysate — which immediately binds and clots around fungi, viruses, and bacterial endotoxins. The sensitive compound has proven useful in testing the safety of surgical equipment and intravenous drugs. Learn more about the the benefits of horseshoe crab blood.

As a result, overfishing of this amazing creature — which predates the dinosaurs by 200 million years — may mean that horseshoe crab populations are in decline.

An article published in The New York Times today breaks down what the loss of the horseshoe crab could mean for the environment, notwithstanding the setbacks it would cause medical research.

For an in-depth look at how the decline of the horseshoe crab could affect just one species — the red knot shorebird — visit NATURE’s “Crash: A Tale of Two Species.”