Like a glassy-eyed old soak, the Madagascan aye-aye has a rule of thumb: the stronger the brew, the better. In their natural habitat, the nocturnal lemurs drink fermented plant nectar. So, to find out if they really do enjoy booze, researchers offered the animals cocktails of varying strengths over the course of a month. It turned out that the more potent the mixture, the more popular it was with the primates. The scientists also offered them water, but it was left untouched. But before you challenge one of the big-eared mammals to a drinking contest, consider this: unlike humans, aye-ayes can quickly break down alcohol thanks to the enzyme alcohol dehydrogenase, which means it’s virtually impossible for them to get drunk. So while you slide off your barstool, the aye-aye will be reaching for the next shot. Chimpanzees also drink alcohol, but show the effects. The chimps regularly imbibe fermented palm sap, which contains 6.9% alcohol.