Not all bonobos read the text books

About a week ago the east bonobos were nested on the west side again. We left camp at 4:35 in the morning, the latest I have left camp to go to the east group. No Bompusa crossing, no mud, no wet feet, what a luxury! By quarter past five we were at the nest site. We heard the bonobos calling before, exceptionally early, and some individuals were already up and heading towards a feeding tree 200 meters further. It took us a while to get round a big tree fall to see who was feeding in the tree. When we finally found a good spot, suddenly the whole group left the tree rapidly and there was some tumult. Five minutes later they came back and started feeding peacefully in the same tree. We saw everyone, including Rita, the subadult female who migrated into the east group during the intercommunity encounter. I just realized the group total of adult individuals was now 12, not 13 (two females emigrated, one immigrated), when Sean noticed a fourth adult male in the group. I checked, one, two, three, and four, he was right. Litono is easy to recognize, but the two other ones are more difficult, and since the end of March I hadn’t seen Dango, a male with a clear scar on his lip and a characteristic wrinkled face. Could this fourth male be Dango again? Before I could confirm his ID, half of the group again left the tree rapidly, chasing or displacing this fourth male in a subtle way. Half an hour later we lost the bonobos as they were travelling east. Probably they crossed the Bompusa soon after. We crossed the river, but didn’t find them for a couple of days. Since that day Sean and I have spent three shifts following the east group, but none of us noticed a fourth male. Today I went with Gottfried to the east. After the first feeding tree some individuals came down to the ground. We were watching one of the males that are hard to identify. I was explaining that one has round nostrils with straight lines above the nostrils, and the male we were watching has a long face, with a high upper lip. However, these face characteristics are a bit subjective and I’m still struggling to distinguish them for sure at all times.  ‘But this male has a totally different face’, Gottfried said. I took my binoculars and I agreed: ‘This is Dango!’ Bonobos are a male-phylopatric species, meaning that the males stay in the group they are born in. Sons stay with their mothers who help them getting a higher dominance status. Daughters migrate between groups, as we saw during the intercommunity encounter. But where was Dango for two months? Did he wander around on his own? Did he temporarily join another group? No one knows. What we do know is that male dispersal has rarely been observed at Lomako, an old bonobo study site. Exceptions confirming the rule? A daughter born in the west group did not disperse before giving birth to her first offspring last January. She did spend some time away from the community, or at least she was regularly not seen for a while, but a couple of months before the birth she came back permanently and mated frequently with all the males in the group. I wonder who the father of her offspring is. A lot of questions to be answered. We still have much to learn about the social behaviour of these long-lived great apes.

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Lieven in congo

At the moment Lieven Devreese is staying at LuiKotale, a bonobo research site of the Max Planck Institute for Evolutionary Anthropology in the vicinity of Salonga National Park, Democratic Republic of Congo. Lieven is a research assistant working on habituation of a second group of bonobos and he hopes to get to see some golden-bellied mangabeys as well. Here you can read more about his 10-month adventure.