The teeth are sheathed in gum like tissue. They are completely covered when the mouth is closed so as not to slice their own mouths up...which they tend to do on occasion anyway. When the mouth opens, they are only partially exposed. When they bite down, the sheath is forced back up into the gum line and the teeth are fully exposed as they embed into prey ...or your arm. Both top and bottom teeth are quite long. Even a fairly young one can sport 3/4 inches or more of teeth. Adults ...
I have a skull somewhere. I should find it for you and take some photos. I never finished cleaning it. I used ants instead of beetles and it's still a little cruddy.
