Cooperative breeding in South American hunter-gatherers
Cooperative breeding in South American hunter-gatherers
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DOI：
10.1098/rspb.2009.1061
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发表时间：
2009-11-07
影响因子：
4.7
通讯作者：
Hurtado, A. Magdalena
中科院分区：
文献类型：
--
作者：
Hill, Kim;Hurtado, A. Magdalena
进化研究人员最近提出，前现代人类社会习惯性地进行合作繁殖，这一特征有助于解释人类的亲社会倾向。尽管有间接证据表明，繁殖后的雌性和配对外的雄性都提供了配对成功繁殖所需的资源，但尚未有研究提供有关不同年龄和性别类别的食物资源流向繁殖者和后代的详细信息，也没有记录帮助者与繁殖者的比例。在这里，我们表明，在南美洲的两个狩猎采集社会中，每对有抚养后代的繁殖对平均得到大约 1.3 个非繁殖成年人的帮助。各个年龄段的年轻已婚男性和未婚男性是主要的食物提供者，占可用于繁殖配对及其后代的所有过剩食物产量的 93-100%。因此，每对有家属的繁殖对平均由 0.8 名成年雄性助手提供。这些数据并没有支持以下假设：在狩猎采集社会中，生育后的女性是年轻生育年龄亲属的主要提供者。人口统计和食物获取数据表明，大多数繁殖对可能会由于觅食运气、健康残疾和中年后代抚养比的累积而出现食物短缺，而额外的供给可能对人类生命史的进化至关重要。
Evolutionary researchers have recently suggested that pre-modern human societies habitually practised cooperative breeding and that this feature helps explain human prosocial tendencies. Despite circumstantial evidence that post-reproductive females and extra-pair males both provide resources required for successful reproduction by mated pairs, no study has yet provided details about the flow of food resources by different age and sex categories to breeders and offspring, nor documented the ratio of helpers to breeders. Here, we show in two hunter-gatherer societies of South America that each breeding pair with dependent offspring on average obtained help from approximately 1.3 non-reproductive adults. Young married males and unmarried males of all ages were the main food providers, accounting for 93-100% of all excess food production available to breeding pairs and their offspring. Thus, each breeding pair with dependants was provisioned on average by 0.8 adult male helpers. The data provide no support for the hypothesis that post-reproductive females are the main provisioners of younger reproductive-aged kin in hunter-gatherer societies. Demographic and food acquisition data show that most breeding pairs can expect food deficits owing to foraging luck, health disabilities and accumulating dependency ratio of offspring in middle age, and that extra-pair provisioning may be essential to the evolved human life history.