Relatedness in wild chimpanzees: Influence of paternity, male philopatry, and demographic factors

• Published in: American journal of physical anthropology Vol. 137; no. 3; pp. 256 - 262
• Main Authors: Inoue, Eiji, Inoue-Murayama, Miho, Vigilant, Linda, Takenaka, Osamu, Nishida, Toshisada
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.11.2008; Wiley-Liss
• Subjects: Age Factors; Animal and plant ecology; Animal Migration; Animal, plant and microbial ecology; Animals; Biological and medical sciences; Chimpanzees; Demecology; Demography; DNA; Female; Females; Fundamental and applied biological sciences. Psychology; genetic diversity; Male; Males; Mammalia; microsatellite; National parks; Pan troglodytes - genetics; Pan troglodytes - physiology; paternity analyses; Physical anthropology; Population Dynamics; Primate genetics; Primatology; relatedness estimation; Sequence Analysis, DNA; Sex Factors; Sexual Behavior, Animal; Social Dominance; Tanzania; Vertebrata; Africa; Tanzania; Population regulation; genetic diversity; Male; Pan troglodytes; Animal migration; paternity analyses; Relatedness; relatedness estimation; Vertebrata; Mammalia; Kinship coefficient; Microsatellite DNA; Primates; Simioidea; microsatellite; Female; Population dynamics; Comparative study
• ISSN: 0002-9483; 1096-8644
• DOI: 10.1002/ajpa.20865

In chimpanzees (Pan troglodytes), high‐ranking males are expected to have high reproductive success and females typically emigrate upon reaching maturity. Although high average relatedness among males in the same social groups has been assumed, previous reports have indicated that relatedness among males is not necessarily significantly higher than that among females. The paternity of 11 offspring and the relatedness of 50 individuals in the M group of chimpanzees at Mahale Mountains National Park, Tanzania, were investigated using DNA analyses. We determined the fathers of 10 offspring. Two different alpha males sired a total of five offspring, whereas the other males had low reproductive success. The proportion of paternal half‐sibling pairs among the 10 offspring was 15.6%. The average relatedness among mature males was significantly higher than that among mature females. The existence of an old male and the long tenure of one alpha male may have contributed to this significant difference. The average dyadic relatedness among mature natal individuals was significantly higher than that in natal‐immigrant pairs in which the individuals came from different groups. The average relatedness among immigrant females was similar to that in pairs of natal and immigrant females, suggesting that the immigrants came from various groups. Thus, female transfer acts to maintain low average relatedness within the group. A comparison of our results to those from other study sites suggests that although the average relatedness among adult males does not reach the level of half‐siblings, under some circumstances it can exceed the relatedness of females. Am J Phys Anthropol, 2008. © 2008 Wiley‐Liss, Inc.