Crabs

Yesterday I did a science class on horseshoe crabs:

Here's what I learned:

I saw 5 horseshoe crabs. All of the alive ones were mating. There was one dead one.

Horseshoe crabs species are shrinking because people are using them to test if drugs are safe.

Horseshoe crabs have blue blood because their blood is based on copper. Our blood is based on iron.