Why Do Horseshoe Crabs Have Copper Blood?

Horseshoe crabs use a copper-based molecule called hemocyanin to distribute oxygen. In nature, copper turns things blue or blue-green. So that’s why their blood is blue; it’s copper-based. Why do crabs have copper blood? While our blood cells bustle around carrying red iron-containing hemoglobin to deliver oxygen to our tissues, Read more…

Do Horseshoe Crabs See?

Eyes. Horseshoe crabs have a total of 10 eyes used for finding mates and sensing light. The most obvious eyes are the 2 lateral compound eyes. These are used for finding mates during the spawning season. Do crabs see with their eyes? The crabs’ eyes are made up of 8,000 Read more…

How Old Is The Oldest Horseshoe Crab?

450 million years old. They’re living fossils. These ocean critters predate the dinosaurs! The oldest known horseshoe crab species, (Lunataspis aurora) was discovered by scientists in 2008 and is estimated to be nearly 450 million years old. How long has the horseshoe crab lived? 445 million yearsHorseshoe crabs are “living Read more…