Horseshoe crabs are marine and brackish water arthropods of the family Limulidae. Their popular name is a misnomer, for they are not true crabs. Given their origin 450 million years ago, horseshoe crabs are considered living fossils. The entire body of the horseshoe crab is protected by a hard carapace. They have a sword-like tail and several sets of eyes which are a million times more sensitive to light at night than during the day. They are carnivorous creatures feeding on worms, molluscs, sometimes crustaceans or even small fish when searching on ocean ground.
