Territoriality, tolerance and testosterone in wild chimpanzees

Sobolewski, Marissa; Brown, Janine L.; Mitani, John C.

doi:10.1016/j.anbehav.2012.09.018

Cited by 45 publications

(51 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our results demonstrate an anticipatory increase in urinary oxytocin in a similar manner to the anticipatory testosterone increase found in intergroup conflicts (28) and intragroup competition (29) in chimpanzees. The observed high urinary oxytocin levels before border patrol initiation suggest that individuals may anticipate imminent intergroup conflict.…”

Section: Resultssupporting

confidence: 64%

Oxytocin reactivity during intergroup conflict in wild chimpanzees

Samuni

Preis

Mundry

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

149

171

View full text Add to dashboard Cite

Intergroup conflict is evident throughout the history of our species, ubiquitous across human societies, and considered crucial for the evolution of humans' large-scale cooperative nature. Like humans, chimpanzee societies exhibit intragroup coordination and coalitionary support during violent intergroup conflicts. In both species, cooperation among group members is essential for individuals to gain access to benefits from engaging in intergroup conflict. Studies suggest that a contributive mechanism regulating in-group cooperation during intergroup conflicts in humans involves the neuropeptide hormone oxytocin, known to influence trust, coordination, and social cognition, although evidence from natural settings is lacking. Here, applying a noninvasive method, we investigate oxytocinergic system involvement during natural intergroup conflicts in wild chimpanzees. We found that chimpanzees of both sexes had significantly higher urinary oxytocin levels immediately before and during intergroup conflict compared with controls. Also, elevated hormone levels were linked with greater cohesion during intergroup conflicts, rather than with the level of potential threat posed by rival groups, intragroup affiliative social interactions, or coordinated behavior alone. Thus, the oxytocinergic system, potentially engendering cohesion and cooperation when facing an out-group threat, may not be uniquely human but rather a mechanism with evolutionary roots shared by our last common ancestor with chimpanzees, likely expediting fitness gains during intergroup conflict.Pan troglodytes | cooperation | group cohesion | neuropeptide | parochial altruism R ecent evolutionary models suggest that parochial altruism,

show abstract

Section: Resultssupporting

confidence: 64%

Oxytocin reactivity during intergroup conflict in wild chimpanzees

Samuni

Preis

Mundry

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

149

171

View full text Add to dashboard Cite

show abstract

“…Furthermore, in contrast to grooming contexts, an existing social bond with the food-sharing partner was not associated with higher oxytocin levels, although it should be noted that there were relatively few food-sharing samples between non-bond partners. Sobolewski et al [69] have shown that food sharing is linked to low urinary testosterone levels in wild male chimpanzees. As in some species, low testosterone is linked to nurturance (i.e.…”

Section: Discussionmentioning

confidence: 99%

Food sharing is linked to urinary oxytocin levels and bonding in related and unrelated wild chimpanzees

et al. 2014

View full text Add to dashboard Cite

Humans excel in cooperative exchanges between unrelated individuals. Although this trait is fundamental to the success of our species, its evolution and mechanisms are poorly understood. Other social mammals also build long-term cooperative relationships between non-kin, and recent evidence shows that oxytocin, a hormone involved in parent-offspring bonding, is likely to facilitate non-kin as well as kin bonds. In a population of wild chimpanzees, we measured urinary oxytocin levels following a rare cooperative event-food sharing. Subjects showed higher urinary oxytocin levels after single food-sharing events compared with other types of social feeding, irrespective of previous social bond levels. Also, urinary oxytocin levels following food sharing were higher than following grooming, another cooperative behaviour. Therefore, food sharing in chimpanzees may play a key role in social bonding under the influence of oxytocin. We propose that food-sharing events co-opt neurobiological mechanisms evolved to support mother-infant bonding during lactation bouts, and may act as facilitators of bonding and cooperation between unrelated individuals via the oxytocinergic system across social mammals.

show abstract

“…For these, samples were not collected on days males hunted, patrolled the boundary of their territory, and followed estrous females, as these behaviors are known or hypothesized to affect testosterone production (Sobolewski et al 2012). Finally, the alpha male was not seen on 20 days that we observed parous females.…”

Section: Urine Collectionmentioning

confidence: 98%

Female parity, male aggression, and the Challenge Hypothesis in wild chimpanzees

2012

Self Cite

View full text Add to dashboard Cite

The Challenge Hypothesis proposes that testosterone mediates aggression during periods of heightened conflict between males, especially episodes that have important fitness consequences. Considerable evidence from seasonally breeding species provides support for this hypothesis, but few data exist in animals that mate yearround. We tested predictions generated by the Challenge Hypothesis in chimpanzees, a non-seasonally breeding primate, through a study of individuals living in an exceptionally large community at Ngogo, Kibale National Park, Uganda. Results indicated that dominance rank had no influence on testosterone levels. Instead of rank influencing testosterone production, additional analyses revealed an important role for reproductive competition. Male chimpanzees displayed more aggression when they were in the same party as parous estrous females than when reproductively active females were unavailable. Male chimpanzees competed more intensely for mating opportunities with parous females than with nulliparas, and as a consequence, males displayed more aggression around the former than the latter. When males accompanied parous estrous females, their urinary testosterone concentrations were significantly higher than baseline concentrations. In contrast, urinary testosterone concentrations did not exceed baseline when males associated with nulliparous estrous females. These differences in testosterone levels could not be attributed to mating per se because males copulated equally often with parous and nulliparous females. Furthermore, variation in testosterone concentrations were not due to males gathering together in large parties, as their levels in these situations did not exceed baseline. Taken together, these findings, derived from a relatively large sample of males and estrous females, replicate those from a prior study and furnish additional support for the Challenge Hypothesis. Our results suggest that the Challenge Hypothesis is likely to be broadly applicable to chimpanzees and increase our understanding of the physiological costs to males who compete for estrous females.

show abstract

Territoriality, tolerance and testosterone in wild chimpanzees

Cited by 45 publications

References 34 publications

Oxytocin reactivity during intergroup conflict in wild chimpanzees

Oxytocin reactivity during intergroup conflict in wild chimpanzees

Food sharing is linked to urinary oxytocin levels and bonding in related and unrelated wild chimpanzees

Female parity, male aggression, and the Challenge Hypothesis in wild chimpanzees

Contact Info

Product

Resources

About