title: Infant Mortality Risk and Paternity Certainty Are Associated with Postnatal Maternal Behavior toward Adult Male Mountain Gorillas (Gorilla beringei beringei).
abstract: Sexually selected infanticide is an important source of infant mortality in many mammalian species. In species with long-term male-female associations, females may benefit from male protection against infanticidal outsiders. We tested whether mountain gorilla (Gorilla beringei beringei) mothers in single and multi-male groups monitored by the Dian Fossey Gorilla Fund's Karisoke Research Center actively facilitated interactions between their infants and a potentially protective male. We also evaluated the criteria mothers in multi-male groups used to choose a preferred male social partner. In single male groups, where infanticide risk and paternity certainty are high, females with infants <1 year old spent more time near and affiliated more with males than females without young infants. In multi-male groups, where infanticide rates and paternity certainty are lower, mothers with new infants exhibited few behavioral changes toward males. The sole notable change was that females with young infants proportionally increased their time near males they previously spent little time near when compared to males they had previously preferred, perhaps to encourage paternity uncertainty and deter aggression. Rank was a much better predictor of females' social partner choice than paternity. Older infants (2-3 years) in multi-male groups mirrored their mothers' preferences for individual male social partners; 89% spent the most time in close proximity to the male their mother had spent the most time near when they were <1 year old. Observed discrepancies between female behavior in single and multi-male groups likely reflect different levels of postpartum intersexual conflict; in groups where paternity certainty and infanticide risk are both high, male-female interests align and females behave accordingly. This highlights the importance of considering individual and group-level variation when evaluating intersexual conflict across the reproductive cycle.
authors: Department of Anthropology, University of California Los Angeles, Los Angeles, California, United States of America.
authors: Stacy
authors: S
authors: Rosenbaum
authors: Dian Fossey Gorilla Fund International, Musanze, Rwanda.
authors: Jean Paul
authors: JP
authors: Hirwa
authors: School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, United States of America.|Institute for Human Origins, Arizona State University, Tempe, Arizona, United States of America.
authors: Joan B
authors: JB
authors: Silk
authors: Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
authors: Linda
authors: L
authors: Vigilant
authors: Dian Fossey Gorilla Fund International, Atlanta, Georgia, United States of America.
authors: Tara S
authors: TS
authors: Stoinski
mesh_terms: D000374:Aggression / Q000523:psychology; D000818:Animals; D000831:Animals, Newborn; D000833:Animals, Suckling; D001522:Behavior, Animal; D003220:Conflict, Psychological; D005260:Female; D006071:Gorilla gorilla / Q000523:psychology*; D006127:Group Structure; D006801:Humans; D008297:Male; D008425:Maternal Behavior / Q000523:psychology; D009026:Mortality; D049590:Postpartum Period / Q000523:psychology*; D012306:Risk; D012725:Sexual Behavior; D012919:Social Behavior; D012930:Social Dominance