title: Comparative study of reproductive skew and pair-bond stability using genealogies from 80 small-scale human societies.
abstract: Genealogies contain information on the prevalence of different sibling types that result from past reproductive behavior. Full sibling sets stem from stable monogamy, paternal half siblings primarily indicate male reproductive skew, and maternal half siblings reflect unstable pair bonds.
  
  
  
  Full and half sibling types are calculated for a total of 61,181 siblings from published genealogies for 80 small-scale societies, including foragers, horticulturalists, agriculturalists, and pastoralists from around the world.
  
  
  
  Most siblings are full (61%) followed by paternal half siblings (27%) and maternal half siblings (13%). Paternal half siblings are positively correlated with more polygynous marriages, higher at low latitudes, and slightly higher in nonforagers, Maternal half sibling fractions are slightly higher at low latitudes but do not vary with subsistence. Partible paternity societies in Amazonia have more paternal half siblings indicating higher male reproductive skew.
  
  
  
  Sibling counts from genealogies provide a convenient method to simultaneously investigate the reproductive skew and pair-bond stability dimensions of human mating systems cross-culturally. Am. J. Hum. Biol. 28:335-342, 2016. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Department of Anthropology and Sociology, Webster University, St. Louis, Missouri, 63119.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Ellsworth
authors.affiliation: Department of Anthropology, University of Missouri, Columbia, Missouri, 65211.
authors.forename: Mary K
authors.initials: MK
authors.lastname: Shenk
authors.affiliation: School of Education, University of California, Irvine, Irvine, California, 92697.
authors.forename: Drew H
authors.initials: DH
authors.lastname: Bailey
authors.affiliation: Department of Anthropology, University of Missouri, Columbia, Missouri, 65211.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Walker
mesh_terms: D005191:Family Characteristics; D005260:Female; D005789:Genealogy and Heraldry; D006801:Humans; D008297:Male; D008393:Marriage; D012098:Reproduction; D035781:Siblings