OK, so here's proof I really have no life lol
I've literally sat and watched my two 4 month olds eat hickory nuts for hours. That sounded wrong, let me revise... LOL I'm not that bad a squammy!!!
I have hours of experience watching them eat hickory nuts (better?)
I'm so obsessive over possible contaminants that I only give nuts with no visible splits or seams, so I know Miss Cass & The Sly Guy are starting from scratch. Their first step is more of a scraping than a direct force. The noise it makes is unreal, LOL kind of has that fingernails-on-chalkboard quality. They break through the shell after several minutes of scraping and usually just chip off a small piece about the size of a green pea to get started. They scoop as much of the meat out of the little hole as they can get using their bottom teeth. When they can't reach any more, they'll turn the nut a little bit and use a slight side angle, combination of mostly top incisors with a little help from their rear jaw teeth, and chip off a bigger section of the shell. This leaves much more meat exposed. Only 1/3 to 1/2 of the shell is left, and its easy pickins from there.
I have a video I've been working on getting posted that's actually titled "Eatin Hickory Nuts", but I can't remember if it shows their technique. I'll put it up in their sorely neglected Nursery thread "Here's... Cassie" here in a few minutes.
Did I mention I have no life?