Horseshoe crabs are ancient marine creatures found along coastlines. Their unique appearance frequently leads to questions about their potential danger, but they do not possess venom, nor do they sting, and are not considered dangerous to humans.
Not Venomous, Not Dangerous
Venom is a toxic substance delivered by certain animals for defense or to capture prey. Horseshoe crabs, in contrast, lack any venom glands or apparatus for injecting toxins.
Despite their intimidating armored appearance and pointed tail, horseshoe crabs are not aggressive. They do not bite or sting, and pose no significant threat to humans. These animals are generally harmless. Their ancient lineage, stretching back over 445 million years, showcases a successful body plan that does not involve venomous defense.
Understanding Their Unique Features
The most prominent feature of a horseshoe crab is its long, pointed tail, known as a telson. This telson is not a stinger and contains no venom. Its function is to help the horseshoe crab right itself if it gets overturned by waves or currents, acting as a rudder for maneuvering.
Horseshoe crabs possess a hard, helmet-shaped exoskeleton that provides protection, with movable spines along their middle section. These are not used offensively against humans. Their mouth is located on their underside, between their legs, and they feed on small invertebrates like worms and clams found in the sand. They do not have teeth or jaws for biting, and their small pincers are too weak to cause harm.
Encountering Horseshoe Crabs
When encountering horseshoe crabs, particularly during their spawning season, it is best to observe them from a distance. If you find one overturned on the beach, it is safe to offer assistance. They can survive out of water for some time, but being upside down can make them vulnerable to the sun.
To help an overturned horseshoe crab, gently pick it up by the sides of its shell, also known as the prosoma. Avoid picking them up by their telson, as this can injure the animal. After righting them, place them back on the sand, ideally facing the water. These creatures play a role in coastal ecosystems, serving as a food source for migratory shorebirds, and their unique blue blood is valuable in medical research for testing the sterility of injectable drugs and vaccines.