Horseshoe Crabs Are Closer to Spiders Than to Crabs

The horseshoe crab has the wrong name. NOAA’s National Ocean Service states that, despite their common name, horseshoe crabs are not really crabs, which are crustaceans, but are more closely related to spiders and scorpions. They are also very old. Atlantic horseshoe crabs have been called living fossils because, according to NOAA, they predate the dinosaurs by more than 200 million years. These animals swarm U.S. coastlines each summer from Maine to Mexico, and Delaware Bay has the largest population of horseshoe crabs in the world. Other animals depend on them. More than 20 species of migratory birds, along with loggerhead sea turtles and many kinds of fish and crabs, rely on the crabs’ eggs as an annual boost to their diets. NOAA notes that horseshoe crab numbers declined in the 1990s and that populations are recovering.