title: Comparative primate obstetrics: Observations of 15 diurnal births in wild gelada monkeys (Theropithecus gelada) and their implications for understanding human and nonhuman primate birth evolution.
abstract: The birth process has been studied extensively in many human societies, yet little is known about this essential life history event in other primates. Here, we provide the most detailed account of behaviors surrounding birth for any wild nonhuman primate to date.
  
  
  
  Over a recent ∼10-year period, we directly observed 15 diurnal births (13 live births and 2 stillbirths) among geladas (Theropithecus gelada) at Guassa, Ethiopia. During each birth, we recorded the occurrence (or absence) of 16 periparturitional events, chosen for their potential to provide comparative evolutionary insights into the factors that shaped birth behaviors in humans and other primates.
  
  
  
  We found that several events (e.g., adopting standing crouched positions, delivering infants headfirst) occurred during all births, while other events (e.g., aiding the infant from the birth canal, licking infants following delivery, placentophagy) occurred during, or immediately after, most births. Moreover, multiparas (n = 9) were more likely than primiparas (n = 6) to (a) give birth later in the day, (b) isolate themselves from nearby conspecifics while giving birth, (c) aid the infant from the birth canal, and (d) consume the placenta.
  
  
  
  Our results suggest that prior maternal experience may contribute to greater competence or efficiency during the birth process. Moreover, face presentations (in which infants are born with their neck extended and their face appearing first, facing the mother) appear to be the norm for geladas. Lastly, malpresentations (in which infants are born in the occiput anterior position more typical of human infants) may be associated with increased mortality in this species. We compare the birth process in geladas to those in other primates (including humans) and discuss several key implications of our study for advancing understanding of obstetrics and the mechanism of labor in humans and nonhuman primates.
authors.affiliation: Department of Anthropology & Environmental Studies Program, California State University, Fullerton, Fullerton, California.|Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway.
authors.forename: Nga
authors.initials: N
authors.lastname: Nguyen
authors.affiliation: School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Lee
authors.affiliation: Department of Anthropology & Environmental Studies Program, California State University, Fullerton, Fullerton, California.|Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Fashing
authors.affiliation: Department of Behavioral Ecology, Johann-Friedrich-Blumenbach Institute for Zoology and Anthropology, University of Göttingen, Göttingen, Germany.
authors.forename: Niina O
authors.initials: NO
authors.lastname: Nurmi
authors.affiliation: Department of Biology, University of Saskatchewan, Saskatoon, Canada.
authors.forename: Kathrine M
authors.initials: KM
authors.lastname: Stewart
authors.affiliation: 908 Willowrock Drive, Loveland, Colorado.
authors.forename: Taylor J
authors.initials: TJ
authors.lastname: Turner
authors.affiliation: 85 S Fair Oaks Ave, Madison, Wisconsin.
authors.forename: Tyler S
authors.initials: TS
authors.lastname: Barry
authors.affiliation: Guassa Gelada Research Project.
authors.forename: Kadie R
authors.initials: KR
authors.lastname: Callingham
authors.affiliation: School of Natural Resources and Extension, University of Alaska Fairbanks, Fairbanks, Alaska.
authors.forename: C Barret
authors.initials: CB
authors.lastname: Goodale
authors.affiliation: Forest Restoration Program, The Nature Conservancy, Bend, Oregon.
authors.forename: Bryce S
authors.initials: BS
authors.lastname: Kellogg
authors.affiliation: Department of Zoology, University of Oxford, Oxford, England, UK.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Burke
authors.affiliation: Department of Microbiology, University of Massachusetts, Amherst, Massachusetts.
authors.forename: Emily K
authors.initials: EK
authors.lastname: Bechtold
authors.affiliation: Windy Ridge, Spring Hill, Little Staughton, Bedford, Bedfordshire, England, UK.
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Claase
authors.affiliation: Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway.
authors.forename: G Anita
authors.initials: GA
authors.lastname: Eriksen
authors.affiliation: School of Biological Sciences, Royal Holloway, University of London, England, UK.
authors.forename: Sorrel C Z
authors.initials: SCZ
authors.lastname: Jones
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Kerby
authors.affiliation: Smithsonian Conservation Biology Institute, Front Royal, Virginia.
authors.forename: Jacob B
authors.initials: JB
authors.lastname: Kraus
authors.affiliation: Department of Anthropology, University of Minnesota, Minneapolis, Minnesota.
authors.forename: Carrie M
authors.initials: CM
authors.lastname: Miller
authors.affiliation: Guassa Gelada Research Project.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Trew
authors.affiliation: Environmental Studies Program California State University Fullerton, Fullerton, California.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Anthropology, University of California, Santa Barbara, Santa Barbara, California.
authors.forename: Evan C
authors.initials: EC
authors.lastname: Beierschmitt
authors.affiliation: Department of Anthropology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Malcolm S
authors.initials: MS
authors.lastname: Ramsay
authors.affiliation: Nova Consulting, New York, New York.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Reynolds
authors.affiliation: Department of Human Evolutionary Biology, Harvard University, Cambridge, Massachusetts.
authors.forename: Vivek V
authors.initials: VV
authors.lastname: Venkataraman
mesh_terms: D000818:Animals; D000885:Anthropology, Physical; D005075:Biological Evolution; D005002:Ethiopia; D005260:Female; D006801:Humans; D007743:Labor, Obstetric / Q000502:physiology*; D036801:Parturition / Q000502:physiology*; D010920:Placenta / Q000502:physiology; D011247:Pregnancy; D016671:Theropithecus / Q000502:physiology*
keywords: fetal emergence pattern; labor; parity; parturition; placentophagy