Behavioural and hormonal responses to predation in female chacma baboons (Papio hamadryas ursinus). Proc Roy Soc Lond B

Princeton University, Princeton, New Jersey, United States
Proceedings of the Royal Society B: Biological Sciences (Impact Factor: 5.05). 04/2006; 273(1587):707-12. DOI: 10.1098/rspb.2005.3378
Source: PubMed


In humans, bereavement is associated with an increase in glucocorticoid (GC) levels, though this increase can be mitigated by social support. We examined faecal GC levels and grooming behaviour of free-ranging female baboons to determine whether similar effects were also evident in a non-human species. Females who lost a close relative experienced a significant increase in GC levels in the weeks following their relative's death compared with the weeks before, whereas control females showed no such increase. Despite the fact that females concentrate much of their grooming on close kin, females who lost a close female relative did not experience a decrease in grooming rate and number of grooming partners; instead, both grooming rate and number of grooming partners increased after a relative's death. While the death of a close relative was clearly stressful over the short term, females appeared to compensate for this loss by broadening and strengthening their grooming networks. Perhaps as a result, females' GC levels soon returned to baseline. Even in the presence of familiar troop-mates and other relatives, females experienced a stress response when they lost specific companions, and they apparently sought to alleviate it by broadening and strengthening their social relationships.

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    • "Several lines of evidence suggest that social bonds are represented in nonhuman primates and variation in affiliation is not always simply the consequence of repeated identical partner choices in small groups. In many primates the probability that former opponents reconcile after a conflict is increased for closely bonded partners (Aureli et al., 2012), males base their coalition partner choice on relationships established in the past (Bergh€ anel, Ostner, Schr€ oder, & Schülke, 2011), individuals modulate their loud calls in reaction to the presence of bonded partners (Micheletta & Waller, 2012), females react with elevated glucocorticoid levels to the death of a partner compared to a nonbonded individual (Engh et al., 2006), and the stronger a male's social bonds the stronger the buffering effects they provide against increasingly strong stressors (Young, Majolo, Heistermann, et al., 2014). Thus, we may be dealing with a phenomenon that is very similar to human friendships (Silk, 2002), which are also characterized by variation in relationship strength, equitability and stability (Allen-Arave, Gurven, & Hill, 2008; Gurven, 2006 ) and which may have evolved as withingroup alliances (DeScioli & Kurzban, 2009). "
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    ABSTRACT: In multimale multifemale primate groups, the strength and stability of affiliative relationships have been shown to affect an individual's long-term fitness such as offspring survival and longevity. Studies investigating the fitness benefits of close social relationships and the underlying mechanisms have mainly focused on the philopatric sex. The strong relationships of philopatric chimpanzee males and baboon females share important characteristics with human friendships in that increased strength of affiliative relationships is associated with increased equitability in service exchanges and relationship stability. So far, it has remained unclear whether the strong relationships of dispersing males share these characteristics as well and can thus be labelled as social bonds. Here we provide results on the variation in affiliative relationship strength and its relation to equitability and relationship stability from two wild groups of male Assamese macaques, Macaca assamensis, at Phu Khieo Wildlife Sanctuary, Thailand collected over 2 and 7 years, respectively. Our analyses of almost 9000 h of focal animal data show that males formed differentiated affiliative relationships and that the strength of a relationship affected how likely males returned a grooming service within a single bout and how equally males were responsible for the maintenance of close proximity. Partner stability among the three strongest relationships was higher than among weaker relationships which suggests that top partners were not retained simply because of a lack of alternatives. Together, these results suggest that dispersing male Assamese macaques form differentiated affiliative relationships that increase in equitability and stability with increasing relationship strength. This is the first study showing long-term partner stability in males as the dispersing sex. Our results thus add to the growing body of literature indicating that nonhuman animals form close social relationships similar to human friendships.
    Full-text · Article · Mar 2016 · Animal Behaviour
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    • "For example, in bi-parental bird species with lifelong monogamy, the death of the partner causes a decrease in the fitness of the surviving individual[91,92]. Similar effects seem also to be present in primates[93]. In many primates, individuals of one sex (typically females) remain within their natal group all their life[94]. "
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    ABSTRACT: Mutual helping for direct benefits can be explained by various game theoretical models, which differ mainly in terms of the underlying conflict of interest between two partners. Conflict is minimal if helping is self-serving and the partner benefits as a by-product. In contrast, conflict is maximal if partners are in a prisoner’s dilemma with both having the pay-off-dominant option of not returning the other’s investment. Here,we provide evolutionary and ecological arguments for why these two extremes are often unstable under natural conditions and propose that interactions with intermediate levels of conflict are frequent evolutionary endpoints. We argue that by-product helping is prone to becoming an asymmetric investment game since even small variation in by-product benefits will lead to the evolution of partner choice, leading to investments by the chosen class. Second, iterated prisoner’s dilemmas tend to take place in stable social groups where the fitness of partners is interdependent, with the effect that a certain level of helping is self-serving. In sum, intermediate levels of mutual helping are expected in nature, while efficient partner monitoring may allow reaching higher levels © 2016 The Author(s) Published by the Royal Society. All rights reserved.
    Full-text · Article · Feb 2016 · Philosophical Transactions of The Royal Society B Biological Sciences
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    • "The endocrine consequences of social buffering were first described in primates (Coe et al., 1978; Mendoza et al., 1978) and primate studies continue to be important particularly for our understanding of natural social buffering in the context of stress. For example in female Chacma baboons, loss of a partner results in elevated CORT and also in enhanced social behaviors such as allogrooming which may help mediate the decline to baseline levels (Engh et al., 2006). Studies of social manipulations in rodents have also played a pivotal role in our understanding of social support on a variety of behavioral, endocrine, and neurobiological outcomes (reviewed in DeVries et al., 2003; Kikusui et al., 2006). "
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    ABSTRACT: The neurobiology of stress and the neurobiology of social behavior are deeply intertwined. The social environment interacts with stress on almost every front: social interactions can be potent stressors; they can buffer the response to an external stressor; and social behavior often changes in response to stressful life experience. This review explores mechanistic and behavioral links between stress, anxiety, resilience, and social behavior in rodents, with particular attention to different social contexts. We consider variation between several different rodent species and make connections to research on humans and non-human primates.
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