Institute for Advanced Study, Kyoto University, Kyoto, Japan.
Wildlife Research Center, Kyoto University, Kyoto, Japan.
PLoS One. 2024 Aug 21;19(8):e0307975. doi: 10.1371/journal.pone.0307975. eCollection 2024.
In a number of species, including humans, perceived outgroup threat can promote ingroup cohesion. However, the distribution and selection history of this association across species with varied intergroup relations remains unclear. Using a sample of 8 captive groups (N = 43 individuals), we here tested whether bonobos, like chimpanzees, show more affiliative ingroup behaviour following perception of outgroup cues (unfamiliar male long-distance vocalisations). We used comparable methods to our previous study of captive chimpanzees, and found that, although weaker, there was an association for more frequent social grooming in response to the outgroup condition than the control condition, alongside more alert posture and increased self-directed behaviour. This provides preliminary evidence for an ancestral origin to the proximate association between outgroup cues and ingroup cohesion, at least prior to the Pan-Homo split, and suggests the presence of intergroup competition in our last common ancestor.
在包括人类在内的许多物种中，感知到的外部群体威胁可以促进内部群体的凝聚力。然而，在具有不同群体关系的物种中，这种关联的分布和选择历史尚不清楚。我们使用了 8 个圈养群体（N=43 个个体）的样本，在这里测试了倭黑猩猩是否像黑猩猩一样，在感知到外部群体线索（陌生雄性远距离叫声）后表现出更多的内部群体亲近行为。我们使用了与我们之前对圈养黑猩猩的研究类似的方法，发现尽管强度较弱，但与对照组相比，对外群体条件的社交梳理更为频繁，同时警觉姿势增加，自我导向行为增加。这为外部群体线索与内部群体凝聚力之间的近因关联提供了初步的证据，至少在 Pan-Homo 分裂之前是这样，并表明我们的共同祖先中存在群体间竞争。
