The scientists found that the social organization of the Guinea baboons has three tiers. The smallest and central units of the society are so-called parties comprising of three to four males with their associated females and their infants. Close social bonds between males are formed within the parties. The next higher level is the gang that consists of two or three parties. Also within the gang, some friendly social interactions between males could be observed. The third level includes all animals that share a home range and is referred to as a community.
"The degree of kinship did not affect the social interaction. The males form close cooperative connections with both related and unrelated conspecifics," says Julia Fischer, head of the Cognitive Ethology Laboratory at the DPZ. Furthermore, the male Guinea baboons showed far less rivalry and fewer aggressions towards females than for example the chacma baboons. Interestingly, traits associated with intersexual competition such as the size of their canine teeth or testicles were also smaller in Guinea baboons than in other species.
"Our results show that a complex social organization builds on the emergence and maintenance of cooperation regardless of the genetic relationships," Julia Fischer explains. Humans live in a multilevel social system as well, where the smallest unit is the family. Within traditional societies, male individuals enter strong cooperative relationships with each other regardless of the degree of kinship. The occurrence of these bonds is associated with the evolutionary development of multilevel societies. "In order to understand our social evolution, non-human primates who live in complex communities are important models," Fischer concludes.
In future studies, the researchers want to investigate the role of females in the male friendships. Perhaps they prefer males with an established network and can thereby contribute to a more intensive friendship between males. (© German Primate Center DPZ, AcademiaNet)