The tolerant chimpanzee - Quantifying costs and benefits of sociality in wild female bonobos (Pan paniscus)

个体的社交方式被认为对健康有直接的影响。因此，动物只有在给个体带来净利益的情况下才会生活在有凝聚力的群体中，而个体只有在强大的联系能提高繁殖成功率的情况下才会形成不同的社会联系。尽管这在行为生态学中是一个标志性的论点，但大型、行动缓慢的哺乳动物的证据积累得很慢。这项研究的具体目的是测试食物资源的社会互动与由此产生的压力反应和精力充沛的后果之间的联系。我们的方法结合了(a)新的焦点树观察方法和(b)新的现场内分泌学方法，这些方法可以产生高时间分辨率的能量平衡。通过这种方法，重复社会互动的累积适应性利益可以根据个体能量平衡的变化来衡量，从而促进生存和繁殖。这项研究的目的是评估关于社会特征进化的竞争性假设，如社会宽容和社会性行为，侏儒黑猩猩或倭黑猩猩与工业化前的人类共有，而不是普通黑猩猩。因此，这项对自然栖息地中唯一的习惯性非供应倭黑猩猩群落的研究有望揭示人类社会行为的进化。

The way individuals socialize is thought to have direct fitness consequences. Accordingly, animals live in cohesive groups only if it conveys net benefits to the individual and individuals form differential social bonds only if strong bonds increase reproductive success. Although this is a hall mark argument in behavioral ecology evidence for large, slow living mammals is accumulating only slowly. The specific aim of the study is to test predictions linking social interactions in food resources to the resulting stress response and energetic consequences. Our approach combines (a) new focal tree observation methods and (b) new field endocrinological methods that yield high temporal resolution of energy balance. With this approach the cumulative adaptive benefit of repeated social interactions can be measured in terms of variation in individual energy balance promoting survival and reproduction. The goal of the study is to evaluate competing hypotheses for the evolution of social traits like social tolerance and socio-sexual behaviors that pygmy chimpanzees or bonobos share with pre-industrial humans but not with common chimpanzees. Thus, this study on the only habituated nonprovisioned community of bonobos in their natural habitat promises to shed light on the evolution of human social behavior.