Horseshoe Crab

ocean · living fossil · arachnid relative · ancient

Not actually crabs. Despite their name, horseshoe crabs aren't crabs or even crustaceans. They're chelicerates, which means they're more closely related to spiders, ticks, and scorpions than to any crab.

Packed with eyes. The horseshoe crab's large dome-shaped shell, called the cephalothorax, houses most of the animal's eyes, limbs, and internal organs. It's this shape that gave the creature its memorable name.

250 million year survivor. Horseshoe crabs have barely changed since they first appeared during the Triassic period around 250 million years ago, earning them the nickname 'living fossils.' Even their ancient ancestors looked remarkably similar.

Three-part body. A horseshoe crab's body is divided into three main sections: the cephalothorax (the big armored dome), the abdomen (the middle section), and the telson (the long pointed tail-like appendage at the back).