Fish of the Day 50 - I got that horseshoe in me

Today's fish (arthropod...) is the horseshoe crab!! Look at those cute eyes!

Horseshoe crab facts:

- Horseshoe crabs aren't actually crabs! Confusing, I know. Despite their name, these creatures are more closely related to spiders and scorpions than to true crabs. They were probably given the name "crab" because of their marine habitats. 

- For some reason, it's a popular belief that their tails contain toxins, but this is not true. Their tail doesn't even serve as a means of self defense. Due to their shell, horseshoe crabs often struggle with being flipped upside down. When this happens, they use their tail to help flip them right side up! They also use it to help them turn while swimming. 

- Horseshoe crabs are "milked". Not for actual milk, but rather their blood. The properties of their copper-rich blood are very useful for testing vaccines, drugs, and other medicines in the medical field, due to how they react to bacterial toxins. This process sadly has a 30% mortality rate among the horseshoe crabs, due to handling, the stress, and the state they are left in once they're released. However, as far as im aware, the actual "milking" process is done in a way that ensures a safe amount of blood is taken.

- Horseshoe crabs can be considered living fossils! They have been around for millions of years, with proof of them existing around 200 million years before the dinosaurs. Even after all that time, it seems like they haven't really changed much, appearence wise. Also, scientists debate if they were related to trilobites. (And, if yes, how closely related)

- They can glow under UV light!

Do you got that horseshoe crab in you? I think I do. I fw this thing alot, especially considering how closely related they are to arachnids.