Animals and alcohol
Laboratory fruit flies and other captive animals get drunk and lots of anecdotal evidence suggests that wild animals can get tipsy too. But we have to be a little careful. Other things can result in what people might interpret as inebriation. Some scientists, for instance, have suggested that stories about moose and deer getting drunk from eating fermented apples are actually stories about animals suffering from acidosis. Acidosis occurs when animals like deer and moose that normally consume difficult to digest carbohydrates suddenly switch over to a diet rich in simple sugars. The bacterial flora in their digestive systems changes with this change in diet and begins to produce too much lactic acid. This lactic acid when absorbed into the bloodstream causes disorientation and can eventually even kill the animals. Apparently, all this can happen within 2-6 hours.
Keeping in mind the possibility of alternative explanations, it could very well be that one of the most graphic examples of mass alcohol intoxication in the animal world may have been the result of insects drinking too much alcoholic flux! In their 1926 paper Insect Visitors to Sap-Exudations of Trees, G. Fox Wilson and N.D. Hort  cite an unpublished manuscript by J. Waterson where Waterston in observing closely the insects feeding at an alcoholic flux site states:
The most remarkable thing, however, about this insect assemblage was that for the most part its members were in a perfectly helpless state. One needed no net to collect specimens — they were to be picked off with the fingers or forceps, and in doing this I became aware that for some feet round the base of the tree there were hundreds upon hundreds of insects laid out in regular zones, and here and there on the bushes round about were others hanging by a leg or legs from leaves or twigs they had just managed to reach before being overcome.
Unlike Waterston, my daughter and I did not see droves of passed out insects. We also didn’t try catching any of the insects so we couldn’t say whether they were any more or less easy to catch. I was, however, able to get very close to some of the butterflies that ordinarily require a longer lens to photograph.
So while it isn’t unreasonable to assume that animals occasionally get drunk in the wild, a more interesting question is whether they ever do it intentionally.