Voluntary Alcohol Consumption in Chimpanzees and Orangutans

Publisher Website
Google Scholar
Abstract
Forty-one chimpanzees (13 males), aged from 4 to 44 years and weighing 16 to 68 kg, and 20 orangutans (10 males), all juveniles, 16.8 to 34.8 kg, on 4 occasions were offered fruit juice or a 10% alcohol-fruit-juice solution (made with 95% ethanol or 40% vodka). Fruit-juice consumption on each occasion ranged from 0 to 4320 ml by the chimpanzees and 0 to 2250 ml by the orangutans; alcoholized fruit juice from 0 to 2400 ml by the chimpanzees and 0 to 1200 ml by the orangutans; consumption time ranged from 1 to 60 min. The subjects drank more of the solution prepared from vodka than from 95% alcohol, and more of the alcohol and grape juice than alcohol and orange or grapefruit juice. Male chimpanzees drank more in general than did females (p< .01), and 54% of the male chimpanzees consumed enough to become intoxicated at least once out of 12 or 24 opportunities compared with 25% of the females. None of the orangutans showed intoxication. Gross physical indices of intoxication, such as locomotor ataxia, did not appear until the chimpanzees had consumed considerably more alcohol than that required to produce ataxia in nonhabituated human beings of comparable size. Heavier animals drank more alcoholized juice than lighter ones (p <.05), except for 1 male chimpanzee in the heaviest group who drank almost none. Age differences could not be taken into account for orangutans since all were captured wild, but chimpanzees drank progressively more up to the fourth decade, when consumption dropped sharply. Placebo consumption also dropped shraply in animals of that age. Fourteen chimpanzees tested first with ethanol solutions and then with vodka drank significantly more vo''dka than animals without previous experience with alcohol (p< .001). Fruit juice consumption matched alcoholized juice consumption to begin with, but tapered off, presumably as animals became accustomed to having large amounts of fruit juice, while consumption of alcoholized juice remained constant.

This publication has 2 references indexed in Scilit: