Horseshoe Crabs

Untitled Slide

Living Fossils

• Horseshoe crabs are most well known because they have not evolved in over 450 million years. They are older than the dinosaurs!

how they help

• Horseshoe crabs may look scary, but are actually some of the most gentle creatures in the ocean.
• They participate in the marine ecosystem by acting as bottom feeders; they eat small crustaceans, clams, worms, and even algae.

how they help, cont'd

• Females lay anywhere between 60 to 120 thousand eggs when they spawn. Their eggs become part of the food chain, and are eaten by migrating shore birds on their way up the coasts of the North American Atlantic.

how they help humans

• Horseshoe crab blood has been used by the FDA to test medical equipment for bio-toxins since the 1970s
• It works by clumping and clotting around bacteria to detect its presence
• Limulus blood is blue, because its main component is copper, as opposed to human blood which is iron based.

how they help humans

• In order to use their blood, we harvest them during certain periods of the year.
• During the extraction process, they are stripped of about 1/3 of their blood content
• 18% of crabs die in the process of blood extraction in the medical field

how humans can help them

• Horseshoe crabs have no physical defense mechanism. Their claws can't pinch, and their telson (tail) is not a stinger, as many people assume!
• They often get stranded on beaches flipped upside down. You can help them by flipping them and assisting them back into the water (gently!) Be careful of their eyes (the bumps on top of their shell) and their tails.

Help your local Horseshoe Crab!