Milk-Bones are "bone" shaped
biscuits for dogs, marketed to
pet owners who want to keep their dogs'
teeth healthy while dispensing a treat at the same time. The biscuits are mostly cornmeal/wheat flour, contain
calcium (and other vitamins & minerals), come in a
tartar control variety, and are manufactured by
Nabisco.
Coincidentally, Nabisco also manufactures
Zwieback, which tastes
just like Milk-Bones, just a little sugary - perhaps this is why kids
gnaw on them? I know I was happiest at age three with a large sized
Milk-Bone in my maw.