Humans may not be the only primates who enjoy an occasional nip. In West Africa, scientists have found a group of chimpanzees who make a habit of pilfering alcoholic drinks.

In Bossou, Guinea, the raffia palm produces a sap whose sugars quickly ferment. Villagers gather the fermented sap and drink it from plastic cups.

Using video cameras, English researchers recorded 51 instances in which chimpanzees raided the villagers’ cups. The chimps use a folded leaf to dip into the cup and then lick the sap off. Sometimes they drink alone, sometimes alternating dips with a companion.

The alcohol content of the palm sap is about 3.1 percent — weak, as cocktails go. The scientists calculated that the chimps drank anywhere from a tenth of an ounce to almost three ounces at a sitting. Males and females were equally interested in and adept at drinking.