That's not why Marines are called jarheads. While we do love the occasional crayon, we're not all stupid.

Jarhead first originated somewhere during WW2 because the high collar on some of our uniforms making it look like our heads were popping out of jars. The term has meant a few other things since then, like referencing the high and tight haircut, or being so "uptight" on their training and discipline and described as having that hat screwed on tight like the lid of a jar.

For the record I read a lot! I love reading. My group of friends in there read a lot. We played tons of RPGs.