UMR 5288 Laboratoire Anthropologie Moléculaire et Imagerie de Synthèse, CNRS, Faculté de Chirurgie Dentaire, 92120 Montrouge, France
Proc Natl Acad Sci U S A. 2018 Jul 3;115(27):E6126-E6134. doi: 10.1073/pnas.1719637115. Epub 2018 Jun 18.
To understand the diversity of human growth and development from an evolutionary point of view, there is an urgent need to characterize the life-history variables of vanishing forager societies. The small body size of the Baka pygmies is the outcome of a low growth rate during infancy. While the ages at sexual maturity, menarche, and first delivery are similar to those in other populations, fertility aspects are unknown. In the Le Bosquet district in Cameroon, thanks to systematic birth records kept from 1980 onwards, we were able to assign ages to individuals with certainty. This study, based on chronological records and on data collected from 2007 to 2017, presents life-history variables related to fertility and mortality among the Baka pygmies: total fertility rate, age-specific fertility rate, completed family size, reproductive span, age at menopause, and infant and juvenile mortality. The Baka present low infant and juvenile mortality, and their fertility pattern differs from that of other forager societies in the higher age-specific fertility rates found in the two lower age classes. Future studies will need to assess whether this particular pattern and the short interbirth interval are related to highly cooperative childrearing, which in the Baka is associated with slow growth. The fertility rate has fallen drastically since 2011, and this matches the arrival of cheap alcohol in the community. Our data provide a first-hand record of the impact of alcohol on fertility in a hunter-gatherer society which appears to be seriously compromising the survival of the Baka.
为了从进化的角度理解人类生长和发育的多样性，迫切需要描述正在消失的狩猎采集社会的生命史变量。巴卡俾格米人的小体型是婴儿期生长速度较慢的结果。虽然性成熟、初潮和首次分娩的年龄与其他人群相似，但生育方面的情况尚不清楚。在喀麦隆的勒博凯区，由于自 1980 年以来系统地保存了出生记录，我们能够确定个体的年龄。这项研究基于时间记录，并结合了 2007 年至 2017 年收集的数据，介绍了与巴卡俾格米人生育力和死亡率相关的生命史变量：总生育率、特定年龄生育率、完整家庭规模、生殖跨度、绝经年龄以及婴儿和青少年死亡率。巴卡俾格米人的婴儿和青少年死亡率较低，其生育模式与其他狩猎采集社会不同，在两个较低的年龄组中发现了更高的特定年龄生育率。未来的研究需要评估这种特殊模式和较短的生育间隔是否与高度合作的育儿方式有关，而在巴卡俾格米人中，这种方式与生长缓慢有关。自 2011 年以来，生育率急剧下降，这与社区中廉价酒精的出现相吻合。我们的数据提供了有关酒精对狩猎采集社会生育力影响的第一手记录，这似乎严重危及了巴卡俾格米人的生存。
