Table 1.

Generation intervals for each chimpanzee and gorilla study community

Mean generation interval, y
TaxaStudy siteNo. offspringFemaleCIMaleCIBoth sexesCI
Western chimpanzeesTaї-North2823.0322.19–23.8023.0522.31–23.8123.0422.48–23.58
Taї-Middle431.7128.34–35.1526.0623.90–28.3228.8926.80–31.03
Taї-South2828.7627.54–29.9825.3624.46–26.3027.0626.29–27.84
Eastern chimpanzeesGombe-Kasekela3124.6224.24–25.0021.8421.75–21.9323.2323.03–23.43
Mahale-M1425.0323.95–26.0819.8719.62–20.1322.4521.90–23.00
Kibale-Ngogo7224.523.80–25.2223.5723.05–24.1324.0423.60–24.48
Kibale-Kanyawara1523.3422.43–24.2528.4227.15–29.7525.8825.04–26.68
Budongo-Sonso3426.0825.03–27.0826.6625.93–27.3426.3725.72–26.95
All chimpanzees22625.1824.86–25.5424.0823.83–24.3424.6324.42–24.85
Mountain gorillasKarisoke9718.1817.97–18.3720.2720.23–20.3019.2219.12–19.32
Bwindi818.2616.87–19.6421.6720.37–22.9319.9718.96–20.88
All gorillas10518.1918.00–18.3920.3720.27–20.4719.2819.17–19.39
Humans*Hunter–gatherers157 societies25.631.528.6
Countries360 societies27.330.829.1
  • * Fenner 2005 (22). Species-wide averages for chimpanzees and gorillas and human values are shown in bold type.