The Horseshoe Crab had started to show up at Cedar Key just the day before we visited. This is one of their breeding grounds.
The female is the larger of the two and the male attaches himself to her so he can fertilize her eggs as she lays them.
The horseshoe crab is one of the oldest species on earth and they have changed little in over 250 millions years. Contrary to popular belief, they really have been around longer than I.
Their blood has no hemoglobin and is blue because it is copper based. Our medical industry uses it and much of what we know about our eyes were learned by studying theirs.