Drunken Monkeys!

Nutritionally speaking, alcohol is a double-edged sword: it’s extremely energy-rich, but it’s also toxic and makes you fall down. So it makes sense that animals which eat fruit would develop a tolerance to alcohol, gaining its energy while avoiding getting so drunk that they start hitting on their predators at the bar. (Or, if you’re a fruit bat, flying into a tree.) And the tolerance these animals have for liquor would put the most gin-blossomed tippler to shame.