A new orphan called Lomela at Lola ya Bonobo Sanctuary is comforted by another bonobo.
Credit: wikimedia
SYDNEY: Unlike their more selfish chimpanzee cousins, bonobos live in a "Peter Pan world" in which they never lose the capacity to share with their friends, a study has found.
Researchers at Duke University in North Carolina and Harvard University in Massachusetts believe the behavioural difference between our two closest living relatives could results from their different habitats and lifestyles.
Bonobos (Pan paniscus) only live in the abundant tropical rainforest forests south of the Congo River and therefore, unlike chimpanzees, do not have to share food with gorillas - or each other - in order to survive.
Evolution makes changes in behaviour
"Not many people have investigated the possibility that evolution can make changes in behavioral and cognitive [development], and that these changes can account for species differences among adults," said Victoria Wobber, evolutionary biologist at Harvard, and a lead author of the study which appeared in the U.S journal Current Biology.
"Here we found that differences in social behavior and cognition among adult bonobos and chimpanzees did derive from the evolution of development. This suggests that similar mechanisms of change may have been at work among apes and potentially in human evolution as well," she said.
In one experiment, researchers gave bonobos the opportunity to keep a pile of food to themselves while a fellow bonobo watched from behind a closed gate. The results were universal - the bonobo always preferred to open the gate to share with its friend.
"They never grow up"
"A chimp would never voluntarily do that," said Brian Hare, an evolutionary anthropologist at Duke University, who participated in the study. "Chimps will do things to help one another, but the one thing they will not do is share food."
Bonobos seem to be living in "a sort of Peter Pan world", according to Hare. "They never grow up, and they share," he said.
Another experiment tested the abilities of the apes to beg for food from humans. In one test two out of three humans held food. The apes were encouraged to touch the hands of the humans with food in order to receive the treat.
In another test, one out of two humans held food concealed in their hand. Once the ape had figured out which human to beg from, the food was moved to the other human.
Beggars can't be sharers
In all of the tests chimps were able to pick up on the necessary patterns required to successfully beg for food much faster than the bonobos.
However, this doesn't mean that bonobos are less intelligent, says Wobber, simply that they have not developed the same social traits a chimp would need to successfully share food "without being slapped on the head".
According to Frans de Waal, a primatologist at Emory University in Atlanta, it has long been thought that bonobos are 'neotenous' compared to chimpanzees - that is, that they retain juvenile characteristics into adulthood.
In fact, it is a characteristic he says they share with human beings.
Bonobos are forever young
"Humans were once declared Homo ludens - the playful primate, as reflected in our love of dance, games, sports and culture, which all have a playful elements," he said. "I see the same quality in bonobos - a forever young species."
However, Frans has some reservations about the results of the study, as he questions the claim that chimpanzees "grow out" of an ability to share food - rather suggesting that it is something they never develop in the first place.
"In my own experience food sharing is not particularly well developed in juvenile chimpanzees, just as it is not very well developed in human children - as every parent knows! - so I am not sure how strong these results are," he said.
"But the idea that bonobos are developmentally delayed compared to chimpanzees seems sound."
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