@article{9b75b25d6a874fc0aa4ac73be15041ca,
title = "Within-individual changes reveal increasing social selectivity with age in rhesus macaques",
abstract = "Accumulating evidence in humans and other mammals suggests older individuals tend to have smaller social networks. Uncovering the cause of these declines can inform how changes in social relationships with age affect health and fitness in later life. While age-based declines in social networks have been thought to be detrimental, physical and physiological limitations associated with age may lead older individuals to adjust their social behavior and be more selective in partner choice. Greater selectivity with age has been shown in humans, but the extent to which this phenomenon occurs across the animal kingdom remains an open question. Using longitudinal data from a population of rhesus macaques on Cayo Santiago, we provide compelling evidence in a nonhuman animal for within-individual increases in social selectivity with age. Our analyses revealed that adult female macaques actively reduced the size of their networks as they aged and focused on partners previously linked to fitness benefits, including kin and partners to whom they were strongly and consistently connected earlier in life. Females spent similar amounts of time socializing as they aged, suggesting that network shrinkage does not result from lack of motivation or ability to engage, nor was this narrowing driven by the deaths of social partners. Furthermore, females remained attractive companions and were not isolated by withdrawal of social partners. Taken together, our results provide rare empirical evidence for social selectivity in nonhumans, suggesting that patterns of increasing selectivity with age may be deeply rooted in primate evolution.",
keywords = "aging, mammals, selectivity, senescence, social behavior",
author = "Siracusa, {Erin R.} and {Negron-Del Valle}, {Josu{\'e} E.} and Daniel Phillips and Platt, {Michael L.} and Higham, {James P.} and Noah Snyder-Mackler and Brent, {Lauren J.N.}",
note = "Funding Information: We are grateful to Josh Firth and two anonymous reviewers, as well as the Editor, for insightful comments on a previous version of this manuscript. We sincerely thank the Caribbean Primate Research Center for maintaining the Cayo population and for access to the study site. We are especially grateful to all the field technicians who have contributed to the long-term behavioral database over the years. We thank members of CRAB at the University of Exeter and members of the CBRU for thoughtful discussion during the manuscript{\textquoteright}s development, as well as Simon Verhulst for consultation regarding the statistical analyses. This work was supported by the following grants from the National Institute of Health (NIH): grant nos. R01-AG060931, R00-AG051764, R01-MH096875, R37-MH109728, R01-MH108627, R01-MH118203, U01MH121260, and R01-NS123054 and the Kaufman Foundation: grant no. KA2019-105548. Cayo Santiago Field Station is supported by the Office of Research Infrastructure Programs of the NIH (2P40OD012217). Funding Information: ACKNOWLEDGMENTS. We are grateful to Josh Firth and two anonymous reviewers, as well as the Editor, for insightful comments on a previous version of this manuscript. We sincerely thank the Caribbean Primate Research Center for maintaining the Cayo population and for access to the study site. We are especially grateful to all the field technicians who have contributed to the long-term behavioral database over the years.We thank members of CRAB at the University of Exeter and members of the CBRU for thoughtful discussion during the manuscript{\textquoteright}s development, as well as Simon Verhulst for consultation regarding the statistical analyses. This work was supported by the following grants from the National Institute of Health (NIH): grant nos. R01-AG060931, R00-AG051764, R01-MH096875, R37-MH109728, R01-MH108627, R01-MH118203, U01MH121260, and R01-NS123054 and the Kaufman Foundation: grant no. KA2019-105548. Cayo Santiago Field Station is supported by the Office of Research Infrastructure Programs of the NIH (2P40OD012217). Publisher Copyright: Copyright {\textcopyright} 2022 the Author(s).",
year = "2022",
month = dec,
day = "6",
doi = "10.1073/pnas.2209180119",
language = "English (US)",
volume = "119",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
publisher = "National Academy of Sciences",
number = "49",
}