Female testosterone, dominance rank, and aggression in an Ethiopian population of hybrid baboons.
Studies on the relationship between female testosterone (T) measures and behavior, particularly in free-ranging primate populations, remain scant. In this study we used fecal steroid analysis to examine the effects of seasonal, reproductive, and social factors on female T in a group of free-ranging hybrid baboons (Papio sp.) in the Awash National Park of Ethiopia. We collected behavioral and hormonal data from 25 adult females across an 11-month period. Solid phase extraction and radioimmunoassay (RIA) techniques were used to quantify T in 776 fecal samples collected weekly from each female. The results indicate that 1) the females had elevated T during pregnancy and during the wet season relative to other periods, 2) female dominance rank was positively related to T measures, and 3) female T and aggression were positively related within subjects but not across subjects. Higher T concentrations during pregnancy are consistent with other published profiles of pregnancy in primates. In combination with data on foraging, wet season increases in T may indicate contest competition for females. The rank-T relationship may be mediated by supplants or aggression. Finally, we discuss the different interpretations of the hormone-behavior relationship based on within- and across-subject analyses.
Beehner
Jacinta C
JC
Department of Anthropology, Washington University, St. Louis, Missouri, USA. jbeehner@princeton.edu
Phillips-Conroy
Jane E
JE
Whitten
Patricia L
PL
D000374:Aggression / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D005243:Feces / Q000737:chemistry; D005260:Female; D010215:Papio / Q000235:genetics / Q000502:physiology*; D011247:Pregnancy; D012098:Reproduction / Q000502:physiology; D012621:Seasons; D012930:Social Dominance; D013739:Testosterone / Q000502:physiology*
D013739:Testosterone