In promiscuous primates, interactions between adult males and infants have rarely been investigated. However, recent evidence suggests that male affiliation towards infants has an influence on several aspects of the infants’ life. Furthermore, affiliations may be associated with male reproductive strategy. In this study, we examined which social factors influenced male-infant affiliation initiated by either male or infant, in wild crested macaques (Macaca nigra). We combined behavioral data and genetic paternity analysis from 30 infants living in three wild groups in Tangkoko Reserve, Indonesia. Our results indicate that adult males and infants do not interact at random, but rather form preferential associations. The social factors with the highest influence on infant-initiated interactions were male rank and male association with the infant’s mother. While infants initiated affiliations with males more often in the absence of their mothers, adult males initiated more affiliations with infants when their mothers were present. Furthermore, males initiated affiliations more often when they were in the same group at the time the infant was conceived, when they held a high dominance rank, or when they had a close relationship with the mother. Interestingly, paternity did not affect male-infant affiliation despite being highly skewed in this species. Overall, our results suggest that adult males potentially associate with an infant to secure future mating with the mother. Infants are more likely to associate with a male to receive better support, suggesting a strategy to increase the chance of infant survival in a primate society with high infant mortality.Significance statementWe explore social relationships between males and infants in a promiscuous primate, the wild crested macaque. Our novel approach addresses the nature of affiliations both from males’ and infants’ perspectives. The results show that males and infants form preferential associations. Male-female affiliation, but not paternity, was a significant predictor of interactions initiated both by males and infants. Males initiated more interactions towards infants when the mother was in proximity, while infants initiated more interactions in her absence. Finally, high-ranking males were more likely to initiate interactions towards infants. We demonstrated that paternity is not a good predictor of male-infant affiliations, even in a species with a high reproductive skew and a relatively high confidence of paternity. Our paper is one of the first to show that infants are active agents in establishing and maintaining preferential relationships with males.

中文翻译：

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雌雄关系，但不是亲子关系，影响野生冠猕猴的雄性-婴儿关系

在混杂的灵长类动物中，成年雄性和婴儿之间的相互作用很少被研究。然而，最近的证据表明，男性对婴儿的归属对婴儿生活的几个方面都有影响。此外，从属关系可能与男性生殖策略有关。在这项研究中，我们研究了哪些社会因素影响了野生冠猕猴（Macaca nigra）中由男性或婴儿发起的男婴关系。我们结合了生活在印度尼西亚 Tangkoko 保护区三个野生群体中的 30 名婴儿的行为数据和遗传亲子关系分析。我们的研究结果表明，成年男性和婴儿不会随机互动，而是形成优先关联。对婴儿发起的互动影响最大的社会因素是男性等级和男性与婴儿母亲的联系。虽然婴儿在母亲不在的情况下更频繁地与男性建立联系，但成年男性在母亲在场时与婴儿建立更多的联系。此外，当男性在婴儿受孕时处于同一群体中时，当他们拥有较高的支配地位时，或者当他们与母亲关系密切时，男性更频繁地发起从属关系。有趣的是，尽管在该物种中高度偏向，但亲子关系并未影响男婴关系。总体而言，我们的研究结果表明，成年男性可能会与婴儿交往，以确保未来与母亲交配。婴儿更有可能与男性交往以获得更好的支持，建议在婴儿死亡率高的灵长类社会中增加婴儿存活机会的策略。意义声明我们探讨了混杂的灵长类动物（野生冠猕猴）中雄性和婴儿之间的社会关系。我们的新方法从男性和婴儿的角度解决了从属关系的性质。结果表明，男性和婴儿形成优先关联。男女关系，但不是亲子关系，是男性和婴儿发起的互动的重要预测因素。当母亲在附近时，男性会与婴儿进行更多的互动，而在母亲不在时，婴儿会与婴儿进行更多的互动。最后，高级男性更有可能开始与婴儿互动。我们证明了亲子关系并不是男婴关系的良好预测指标，即使在具有高繁殖偏差和亲子关系相对较高置信度的物种中也是如此。我们的论文是第一个表明婴儿是建立和维持与男性优先关系的积极因素之一。