Horseshoe crabs looks like little tanks crawling on the shallow ocean floor. These animals plow along, searching for food and using their strong legs to crack open shellfish and devour the tasty insides. These creatures have been prowling the seas for about 500 million years, and still look very much the way they did eons ago.
Live Long: A nearly impenetrable, helmet-like suit of armor has helped horseshoe crabs survive in the ocean for a long time. In fact, horseshoe crab fossils have been found from 500 million years ago, when life was first developing on the planet.
Safe Spear: This crab's stiff tail looks like a dangerous weapon, but the creature never uses it against enemies. The horseshoe crab uses its tail to push its body downward when digging into the sand for food or shelter, and to flip itself over if it ever ends up on its back.
Cracking Down[]
The horseshoe crab scuttles along the seafloor looking for food.
Horseshoe crabs spend their lives walking along shallow seabeds, eating up any morsels they can find. These crabs are slow movers, so their meals are usually shellfish, worms and carrion. Special chemical receptors help the creatures detect prey buried in the sand from up to 3 feet away. When they find buried clams, horseshoe crabs dig quickly with their hind legs, then use these same legs to crush the victim's shell. Spikes on the crabs' legs help tear meat from the shell and carry it to their mouths.
Four-Eyed: The horseshoe crab has four eyes, but they can't see an image the way human eyes do. They can only sense movement and tell the difference between light and dark. If a predator casts a shadow over it, the crab quickly burrows into the sand to hide.
Beach Bash: Once every spring, during the highest tide of the season, mobs of horseshoe crabs crawl up to the beach to breed. Males grab onto a female's shell with their pincer-like feet as she digs into the sand and lays her eggs.
Crab Up Close[]
- The horseshoe crab's tough armor is actually made of two separate shells. The shells are hinged together so the crab can bend its rear half for leverage when digging. Small but sharp spikes on the rear portion of the shell give the crab extra protection.
- On the underside, the crab has five pairs of legs (a), all of which it uses for walking and tearing up the flesh of prey. The horseshoe crab's gills (b) overlap each other like flaps behind its legs; each gill contains up to 200 membranes that take oxygen from the water.
Trading Card[]
Trivia[]
- The knowledge card is titled Horseshoe Crabs, the trading card is titled Horseshoe Crab.
- The main blurb on the front of the card mistakenly pluralizes both "crabs" and "looks".
- The horseshoe crab is mentioned as a living relative to Trilobites in the latter's Did You Know? section on their knowledge card.
- The horseshoe crab is featured on several Monster Mania cards:
- It is first featured in It's All Relative! on Monster Mania 30.
- Despite the Monster Mania card being from a packet before the crab's knowledge card, its trading card does come before.
- It is later featured in Toxic Trouble on Monster Mania 54.
- It is first featured in It's All Relative! on Monster Mania 30.