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<\/div>Bonobos often act aggressively, despite their peaceful reputation<\/p>\n
Sergey Uryadnikov \/ Alamy Stock Photo<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n
Have we misjudged our two closest relatives? Chimpanzees are known for lethal violence while bonobos are widely seen as paragons of peaceful coexistence, free love and female empowerment \u2013 but a new study suggests that the reality is more complicated.<\/p>\n
Maud Mouginot<\/a> at Boston University in Massachusetts says she has always thought bonobos\u2019 peaceful reputation was \u201cvery reductionist\u201d.<\/p>\n To compare the differences in aggression between bonobo and chimpanzee males, she and her colleagues followed 12 males from three bonobo communities at the Kokolopori Bonobo Reserve in the Democratic Republic of the Congo and 14 males from two chimpanzee communities at Gombe National Park in Tanzania.<\/p>\n The researchers tracked each of the primates from when they woke up each morning to when they returned to their nests to sleep at night, recording details of every aggressive incident. Altogether, they logged over 2000 hours following the bonobo males and over 7300 hours tracking chimpanzees.<\/p>\n Aggressive behaviours included contact aggression \u2013 such as hitting, pulling, biting or kicking \u2013 and non-contact aggression, such as charging and chasing.<\/p>\n The team found that bonobo males had 2.8 times as many aggressive interactions as chimp males in total, and three times as many incidents of contact aggression.<\/p>\n <\/p>\n However, chimp aggression was more likely to involve coalitions of males and to be directed towards females, whereas male bonobo aggression towards females was extremely rare.<\/p>\n \u201cI was not expecting to find such rates of aggression among [bonobo] males,\u201d says Mouginot.<\/p>\n Bonobo males that acted more aggressively towards other males were more likely to mate with females while they were fertile.<\/p>\n According to Mouginot, one explanation for why bonobos act more aggressively could be the differences in bonobo and chimpanzee coalitions, which change the costs and benefits of aggression.<\/p>\n \u201cIn bonobos, females form coalitions but rarely males,\u201d she says. \u201cIn chimpanzees, males form coalitions against within-group males or to defend a territory. Therefore, if one [chimpanzee] male acts aggressively against another one, he might face a coalitionary retaliation.\u201d<\/p>\n But for male bonobos, the risk of provoking a group response is lower, so the consequences of aggression are more predictable and less dangerous, she says.<\/p>\n The study also found that male-female interactions are very different between the two species. In bonobos, males avoid acting aggressively towards females and they form close associations with them.<\/p>\n Mouginot says she doesn\u2019t think that conclusions can be drawn from this about any traits that humans might share with chimpanzees, bonobos or a common ancestor.<\/p>\n \u201cResearchers often refer to chimpanzees, or sometimes bonobos, as the \u2018best model\u2019 for our last common ancestor,\u201d she says. \u201cI think none of those species are a good model \u2013 they all went through their own evolutionary path. What is interesting is to look at how some strategies evolve in some species and not others.\u201d<\/p>\n Joan Silk<\/a> at Arizona State University says this data suggests that bonobo males are at least as aggressive as chimpanzee males, which isn\u2019t what we would expect of \u201cpeaceful\u201d apes. It will be important to look at other groups of bonobos and chimpanzees to see if the results are replicated, she adds.<\/p>\n