title: Maternal Behavior and Physiological Stress Levels in Wild Chimpanzees (Pan troglodytes schweinfurthii).
abstract: Individual differences in maternal behavior toward, and investment in, offspring can have lasting consequences, particularly among primate taxa characterized by prolonged periods of development over which mothers can exert substantial influence. Given the role of the neuroendocrine system in the expression of behavior, researchers are increasingly interested in understanding the hormonal correlates of maternal behavior. Here, we examined the relationship between maternal behavior and physiological stress levels, as quantified by fecal glucocorticoid metabolite (FGM) concentrations, in lactating chimpanzees,Pan troglodytes schweinfurthii, at Gombe National Park, Tanzania. After accounting for temporal variation in FGM concentrations, we found that mothers interacted socially (groomed and played) with and nursed their infants more on days when FGM concentrations were elevated compared to days when FGM concentrations were within the range expected given the time of year. However, the proportion of time mothers and infants spent in contact did not differ based on FGM concentrations. These results generally agree with the suggestion that elevated GC concentrations are related to maternal motivation and responsivity to infant cues and are the first evidence of a hormonal correlate of maternal behavior in a wild great ape.
authors.affiliation: Center for the Advanced Study of Hominid Paleobiology, The George Washington University, Washington, DC 20052.
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Stanton
authors.affiliation: Department of Conservation and Science, Lincoln Park Zoo, Chicago, Illinois 60614; and Committee on Evolutionary Biology, University of Chicago, Chicago, Illinois 60637.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Heintz
authors.affiliation: Department of Psychology, Franklin and Marshall College, Lancaster, Pennsylvania 17604.
authors.forename: Elizabeth V
authors.initials: EV
authors.lastname: Lonsdorf
authors.affiliation: Department of Conservation and Science, Lincoln Park Zoo, Chicago, Illinois 60614; and Committee on Evolutionary Biology, University of Chicago, Chicago, Illinois 60637.
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Santymire
authors.affiliation: Gombe Stream Research Centre, Gombe, Tanzania.
authors.forename: Iddi
authors.initials: I
authors.lastname: Lipende
authors.affiliation: Center for the Advanced Study of Hominid Paleobiology, The George Washington University, Washington, DC 20052.
authors.forename: Carson M
authors.initials: CM
authors.lastname: Murray
keywords: Glucocorticoids; Maternal investment; Mother–infant; Stress