TY - JOUR
T1 - Social bonds in the dispersing sex
T2 - Partner preferences among adult female chimpanzees
AU - Foerster, Steffen
AU - McLellan, Karen
AU - Schroepfer-Walker, Kara
AU - Murray, Carson M.
AU - Krupenye, Christopher
AU - Gilby, Ian
AU - Pusey, Anne E.
N1 - Funding Information:
We thank Tanzania National Parks, the Tanzania Wildlife Research Institute, and the Tanzanian Commission for Science and Technology for granting us permission to work on this project in Gombe National Park. We also thank the Jane Goodall Institute for funding data collection at Gombe, the Gombe Stream Research Center staff for data collection, and Dr Jane Goodall for granting us permission to work with the long-term data set. Additional funding was provided by National Science Foundation grants DBS-9021946 , SBR-9319909 , BCS-0452315 , IOS-LTREB-1052693 and DGE-1106401 , and by National Institutes of Health grants R01-AI058715 and R00-HD057992 . We thank Allison Rogers for help with data extraction, Joseph Feldblum for his assistance with rank calculations and Roger Mundry for helpful discussions on multivariate modeling.
Publisher Copyright:
© 2015 The Association for the Study of Animal Behaviour.
PY - 2015/7/1
Y1 - 2015/7/1
N2 - In most primate societies, strong and enduring social bonds form preferentially among kin, who benefit from cooperation through direct and indirect fitness gains. Chimpanzees, Pan troglodytes, differ from most species by showing consistent female-biased dispersal and strict male philopatry. In most East African populations, females tend to forage alone in small core areas and were long thought to have weak social bonds of little biological significance. Recent work in some populations is challenging this view. However, difficulties remain in quantifying the influence of shared space use on association patterns, and in identifying the drivers of partner preferences and social bonds. Here, we use the largest data set on wild chimpanzee behaviour currently available to assess potential determinants of female association patterns. We quantify pairwise similarities in ranging, dyadic association and grooming for 624 unique dyads over 38 years, including 17 adult female kin dyads. To search for social preferences that could not be explained by spatial overlap alone, we controlled for expected association based on pairwise kernel volume intersections of core areas. We found that association frequencies among females with above-average overlap correlated positively with grooming rates, suggesting that associations reflected social preferences in these dyads. Furthermore, when available, females preferred kin over nonkin partners for association and grooming, and variability was high among nonkin dyads. While variability in association above and below expected values was high, on average, nonkin associated more frequently if they had immature male offspring, while having female offspring had the opposite effect. Dominance rank, an important determinant of reproductive success at Gombe, influenced associations primarily for low-ranking females, who associated preferentially with each other. Our findings support the hypothesis that female chimpanzees form well-differentiated social relationships that are of potential adaptive value to females and their offspring.
AB - In most primate societies, strong and enduring social bonds form preferentially among kin, who benefit from cooperation through direct and indirect fitness gains. Chimpanzees, Pan troglodytes, differ from most species by showing consistent female-biased dispersal and strict male philopatry. In most East African populations, females tend to forage alone in small core areas and were long thought to have weak social bonds of little biological significance. Recent work in some populations is challenging this view. However, difficulties remain in quantifying the influence of shared space use on association patterns, and in identifying the drivers of partner preferences and social bonds. Here, we use the largest data set on wild chimpanzee behaviour currently available to assess potential determinants of female association patterns. We quantify pairwise similarities in ranging, dyadic association and grooming for 624 unique dyads over 38 years, including 17 adult female kin dyads. To search for social preferences that could not be explained by spatial overlap alone, we controlled for expected association based on pairwise kernel volume intersections of core areas. We found that association frequencies among females with above-average overlap correlated positively with grooming rates, suggesting that associations reflected social preferences in these dyads. Furthermore, when available, females preferred kin over nonkin partners for association and grooming, and variability was high among nonkin dyads. While variability in association above and below expected values was high, on average, nonkin associated more frequently if they had immature male offspring, while having female offspring had the opposite effect. Dominance rank, an important determinant of reproductive success at Gombe, influenced associations primarily for low-ranking females, who associated preferentially with each other. Our findings support the hypothesis that female chimpanzees form well-differentiated social relationships that are of potential adaptive value to females and their offspring.
KW - Chimpanzee social structure
KW - Core area
KW - Dyadic association
KW - Kin bias
KW - Range estimation
KW - Social bonding
KW - Social preference
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U2 - 10.1016/j.anbehav.2015.04.012
DO - 10.1016/j.anbehav.2015.04.012
M3 - Article
AN - SCOPUS:84929623088
SN - 0003-3472
VL - 105
SP - 139
EP - 152
JO - Animal Behaviour
JF - Animal Behaviour
ER -