Caught! These two chimpanzees in the Taï National Park in the Ivory Coast are in the process of eating the plum -like fruits of a tree. The highlight: the fruits are already partially fermented and therefore contain alcohol. For the first time, a research team around Aleksey Maro from the University of California at Berkeley examined how great the alcohol content of this and other fruits is in the monkey’s habitat.
Biologists have often observed monkeys, birds, elephants and other fruit -eating animals as they consume overgrown alcohol -containing fruits. So far, however, it was unclear how high the alcohol content of such fruits is – and how “drunk” the animals are.
That is why a team led by Aleksey Maro from the University of California in Berkeley in the Taï National Park and in the Kibale National Park in Uganda collected fruits of trees, of which chimpanzees often ate, and then determined their alcohol content. “The chimpanzees eat five to ten percent of their body weight on tire fruits every day, so that even low concentrations result in a high daily amount of daily quantity – a considerable dose of alcohol,” explains senior author Robert Dudley.
The analyzes of the fruits showed: “At all locations, male and female chimpanzees take around 14 grams of pure ethanol per day with food, which corresponds to an American standard drink,” explains Maro. “If you take the body mass into account because chimpanzees weigh about 40 kilos while a typical person weighs 70 kilos, the amount increases on almost two drinks.”
But don’t the monkeys get drunk by their sweets? The chimpanzees eat the fruits throughout the day, but do not show any obvious signs of intoxication, explains Maro. In order to be drunk by the fermented fruits alone, the monkeys would have to eat so much from the fact that their stomach flows up.
It has not yet been clear whether the great apes are particularly targeting alcohol -containing fruits and are specifically looking for them. Nevertheless, the high -proof fruits seem to be a regular part of their diet. According to one theory, the chimpanzees could specifically look for fruits with alcohol smell because this shows particularly sugar -containing food – and the more sugar -containing food, the more energy it can provide the animals.
However, it is also conceivable that the joint consumption of alcoholic fruits in primates or other animals contributes to social bonds, explain the researchers. In addition, alcohol could increase the enjoyment of the meal, similar to a glass of wine at dinner. “The human affinity for alcohol has probably arisen from this nutrition height of our joint ancestor with the chimpanzees,” explains Maro.