Chimpanzee Cooperation Linked to Hormone; Sharing and Caring
Chimps don't just share, they also care. Researchers have found out exactly why unrelated chimpanzees will cooperate with each other outside of a sexual relationship.
The study, published in the journal Proceedings of the Royal Society B, looked at the social interactions of wild chimps. Researchers tested the urine of the chimpanzees in Uganda in order to measure the animals' levels of oxytocin after grooming sessions. Oxytocin, a hormone associated with forming mother-baby and pair bonds, had not been implicated in non-kin relationships before now. In other words, the chemical was not associated with the formation of "friendships." Nonetheless, researchers hoped to see a rise in the oxytocin levels of the chimps after their grooming sessions.
Relationships are important in chimp society. "Friendships" between female-female pairs and male-male pairs often occur and give them greater longevity and increased rates of offspring survival. Cooperative behavior between these chimps includes food sharing, collaborative hunting, and grooming. Like humans, these apes will maintain relationships with others that they're not related to and not in a sexual relationship with.
The scientists noted that while oxytocin levels rose after grooming sessions between bonded pairs of chimps-that is, chimps that have already formed friendships-increased levels did not occur between non-bond partners.
According to BBC News, the researchers hypothesized that the social bonds that chimps form possibly have a psychological component, which would explain why oxytocin levels didn't increase between non-bonded pairs. Nonetheless, the study does support the notion that enduring relationships between animals are not purely cognitive, but also have a hormonal component.
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