Yet Another Non-Unique Human Behaviour: Leave-Taking in Wild Chacma Baboons (Papio ursinus)

Abstract

Leave taking is a common, possibly universal, feature of human social behaviour that has undergone very little empirical research. Although the importance remains unknown, it has been suggested to play an important role in managing separations, mitigating the risk, and increasing social bonding beyond the interaction itself. In nonhuman species, the literature is virtually absent, but identifying leave taking beyond humans may provide unique insights into the evolutionary history of this behaviour and shed light onto its proximate and ultimate function(s). Methods to study leave taking are not well-established, and the variation in definitions, measures, and control variables presented in past studies poses additional challenges. Baboons are a valuable model for investigating human behavioural evolution: as a flexible, highly adaptable, and social primate whose radiation is, similarly to humans, associated with the emergence of the African savannah biome. Using the framework and definition proposed by Baehren, we investigated the presence of leave taking in a wild, generalist primate and tested a range of candidate behaviours on prerecorded video footage: (1) self-scratching, (2) eye gaze, and (3) orientation in the direction of parting. Using multivariate analysis, controlling for interaction duration and individual variation, our results show that orientation in the direction of parting occurs predominantly before social separation events. These results indicate evidence of leave taking in a wild nonhuman population and contrast with previous ideas that this is a uniquely human behaviour. The presence of leave taking in baboons suggests a deep evolutionary history of this behaviour, warranting further investigation into its function and presence across other nonhuman primate species.

A network-based analysis of signal use during approach interactions across sexes in chacma baboons (Papio ursinus griseipes)

“…All adult and subadult baboons were identified and named by JM in 2019 and can successfully be identified in situ and from sufficiently high-resolution video footage. Sixty-five hours of footage were recorded opportunistically during October and November 2018 and between July and November 2019 by colleague Lucy Baehren and JM [64]. Recording focused on groups of baboons, with target group rotated throughout the day, but was not randomized as individuals had not been identified at the time of recording.…”

Editorial: Recent Advances in Animal Cognition and Ethology

“…In Nepal, an etho-ethnographic study examined the social behaviour of domestic yaks, demonstrating the role of cultural values in herd cohesion [ 23 ]. In a separate investigation, researchers observed leave-taking behaviour in wild chacma baboons [ 24 ], challenging the notion that this behaviour is unique to humans and suggesting a deep evolutionary history. Several studies used innovative approaches to understand complex animal societies and networks.…”

“…It proved effective in uncovering complex natural behaviours. Video footage and multivariate analysis were instrumental in identifying behavioural cues associated with leave-taking in wild chacma baboons [ 24 ]. These advanced analysis techniques shed light on social behaviours in non-human populations.…”

“…This technology allowed researchers to analyse extensive datasets without any harm to the indris or their habitat. Leave-taking behaviour in wild chacma baboons [ 24 ] was investigated using video footage and multivariate analysis, which do not require direct contact with the animals as for the use of drones in studying multilevel animal societies, while groundbreaking, does not compromise animal welfare. Drones provide a non-invasive means of observing and tracking animals within their natural habitats [ 26 ].…”

Conceptual Archaeology of a Temporal Place: Albert and Kessler (1976) Applied to Chacma Baboons (Papio ursinus)

“…Introduction to the temporal place just like human encounters, animal encounters must come to an end. There has been a recent increase in the interest surrounding non-human primate leave-taking, defined as behaviors occurring at the end of social separation (Baehren, 2022), with evidence that chimpanzees (Heesen et al, 2021) and baboons (Baehren and Carvalho, 2022) end social interactions with specific behaviors that are comparable to those of humans, such as gestural and postural changes. Such interaction endings represent temporary pauses of continuity within ongoing relationships and (Albert and Kessler, 1976) milestone paper outlines a variety of proximate mechanisms to understand these endings.…”