We found this dead horseshoe crab on the beach today. It had a numbered tag on its shell apparently put there by The Maryland Fish & Wildlife Conservation Office. I've seen many horseshoe crabs here over the years, but never one with a tag. I made sure to go to the website and log it.
Imagine you had never seen a crab before. Then someone shows you a picture of a true crab and says "this is a crab". Now imagine after that you are shown a horseshoe crab. There's no way you would think that's also a crab.