Max Planck Institute for Evolutionary Anthropology
Deutscher Platz 6
phone.: +49 (341) 3550 - 0
fax: +49 (341) 3550 - 119
Contact: Sandra Jacob (e-mail: info@[>>> Please remove the brackets! <<<]eva.mpg.de, phone: +49 (0) 341-3550 122)
An interactive world map of human genetic history reveals likely genetic impacts of historical events
When individuals from different groups interbreed, their offspring's DNA becomes a mixture of the DNA from each admixing group. Pieces of this DNA are then passed along through subsequent generations, carrying on all the way to the present day. Researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, Oxford University and University College London (UCL) have now produced a global map detailing the genetic histories of 95 different populations across the world, spanning the last four millennia.
Several thousand chimpanzees inhabit a remote forest area in the northern Democratic Republic of the Congo
With great ape populations in fast decline, it is crucial to obtain a global picture of their distribution and abundance, in order to channel and direct conservation activities to where they are most needed. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and the University of Amsterdam in The Netherlands conducted hundreds of kilometers of chimpanzee surveys at multiple sites in the Central Uele region of northern Democratic Republic of the Congo and discovered a large, continuous population of Eastern chimpanzees (Pan troglodytes schweinfurthii). The population in the remote Bili-Gangu forest was surveyed in 2005 with line transects and again in 2012, and appears to have remained stable. The total area surveyed, which encompasses about 50,000 square kilometers, is home to several thousands of chimpanzees and, according to the researchers, should be considered a priority site for conservation of the eastern subspecies.
Chimpanzees keep track of other group members’ bonding partners and use this knowledge in conflict situations
To know who your opponents’ family and friends are can be of advantage in a conflict situation. Humans make predictions about other people’s social relationships frequently. Whether other animals also have the cognitive skills to track their group mates’ social relationships across time and beyond close kin has so far not been known. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig have now conducted playback experiments with wild-living chimpanzees from Budongo Forest in Uganda. Two hours after a subject attacked or had been attacked by an opponent, the researchers broadcast the recording of a third individual’s aggressive barks from a speaker near the subject. If the call provider was their opponent’s close buddy or kin, subjects looked longer and moved away more often from barks than if the call provider was not a bond partner. This shows that chimpanzees know who their group mates’ kin or non-kin bond partners are and that their behavior may have an impact on them.
Chimpanzees who share their food with others have higher levels of the hormone oxytocin in their urine
The ability to form long-term cooperative relationships between unrelated individuals is one of the main reasons for human’s extraordinary biological success, yet little is known about its evolution and mechanisms. The hormone oxytocin, however, plays a role in it. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, measured the urinary oxytocin levels in wild chimpanzees after food sharing and found them to be elevated in both donor and receiver compared to social feeding events without sharing. Furthermore, oxytocin levels were higher after food sharing than after grooming, another cooperative behaviour, suggesting that food sharing might play a more important role in promoting social bonding. By using the same neurobiological mechanisms, which evolved within the context of building and strengthening the mother-offspring bond during lactation, food sharing might even act as a trigger for cooperative relationships in related and unrelated adult chimpanzees.