Bears! Except they don't actually subsist on berries the way some species of birds do. It's a little hard to subsist entirely on berries in a temperate climate -- they aren't around long enough to feed on through even the summer. Coined around 1660 from Latin roots bacca, berry + -vorus, devouring.
When the blackberries ripened, my mother would send me out with a basket, not worrying about how much came to the house in my baccivorous hands.