Raccoon hat?
What's wrong with you people, that's no raccoon, it's a badger hat.
Just because it's an old timey photo of a guy with a hunk of fur on his head and everyone thinks it's a raccoon. (BTW, Daniel Boone never wore a raccoon hat, but Davy Crockett did).
Seriously though, if you look at the shape of the head of the animal, how pointed it is, it's not a raccoon, which has a more blockier-type face; the shape of the head better fits that of a badger. And a badger has a reputation of being a fierce fighter and is from the northern parts of the U.S., which would fit a man that enlisted from Illinois. And speaking of fit, isn't that hat about two sizes too small?