You may have seen the odd-looking creature known as the horseshoe crab washed up on a beach. Its body is covered by an armored shell with pointed barbs, and it has a long tail. But the horseshoe crab is not horseshoe-shaped, and it’s not a real crab either!
All real crabs are crustaceans, like lobsters and shrimps. But the horseshoe crab is an arachnid, like spiders and scorpions!
The horseshoe crab is one of the oldest things on earth, its body hasn’t changed its form in more than 200 million years!