Olfactory cognition of social relationships in primates

嗅觉是动物进化史上最古老的感官之一，在许多哺乳动物的社会认知和交流中起着关键作用。嗅觉对社会生活的重要性在进化上更古老的灵长类动物类群中也得到了很好的证实，如狐猴和懒猴。然而，卡他鼻灵长类（旧大陆的猴子和猿）由于其强烈的视觉定向，在历史上被认为很少依赖嗅觉。虽然这一概念越来越被认为是过时的，但它导致了这些分类群中嗅觉研究的稀缺。这一点至关重要，因为卡他鼻科动物被认为是具有最复杂社会关系的灵长类动物。管理这些关系带来了相当大的认知挑战，需要动物获得有关同种的社会知识，并随着时间的推移跟踪自己和他人的社会互动。由于嗅觉线索可以提供其他感官领域（暂时）缺乏的社会信息，或增强其他感官线索的精确性和可靠性，因此它们可以为管理这些复杂的关系做出重大贡献。即便如此，卡他鼻灵长类动物对社会属性和关系的识别主要是在视觉和听觉领域进行研究的。关于嗅觉在卡他鼻社会认知中的作用的研究严重缺乏，这在我们对灵长类动物交流和社会复杂性进化的理解中构成了一个重大的空白。因此，拟议的项目将评估巴巴利猕猴（Macaca Macacus）对社会关系的嗅觉认知，巴巴利猕猴是一种具有复杂社会关系的旧世界猴，已知可以使用视觉和听觉线索识别个人属性和社会关系。我们将采用一种强大的，综合的方法，结合分析巴巴利猕猴气味的化学成分与同种气味的实验演示。为此，我们将使用最先进的非侵入性采样协议，高灵敏度气相色谱-质谱分析和完善的认知测试范式。特别是，我们将确定哪些基本的（身份，亲属关系，等级）和派生（第三方，组组成）的社会信息可以从两个习惯的，半自由的生活在自然的社会环境中的人群的巴巴利猕猴的气味。通过将气味成分中包含的信息与猴子使用嗅觉线索识别个体属性和社会关系相关联，该项目将大大有助于理解管理社会关系的嗅觉机制和认知基础，以及灵长类动物沟通和社会复杂性的演变。

The sense of smell is among the evolutionarily oldest of the animal senses and plays a pivotal role in social cognition and communication in numerous mammals. The importance of olfaction for social life is also well-established in evolutionarily older primate taxa such as lemurs and lorises. Catarrhine primates (Old World monkeys and apes), however, have historically been assumed to rely little on the sense of smell due to their strong visual orientation. Although this notion is increasingly considered outdated, it has resulted in a scarcity of olfactory studies in these taxa. This is vital insofar as catarrhines are considered to be the primates with the most complex social relationships. Managing these relationships poses considerable cognitive challenges, requiring animals to obtain social knowledge about conspecifics and to track their own and others' social interactions over time. As olfactory cues can provide social information that is (temporarily) absent in other sensory domains or enhance the precision and reliability of other sensory cues, they could contribute significantly to managing these intricate relationships. Even so, the recognition of social attributes and relationships in catarrhine primates has been studied primarily in the visual and auditory domain. This severe paucity of studies on the role of olfaction in catarrhine social cognition poses a significant gap in our understanding of primate communication and the evolution of social complexity. The proposed project will therefore assess olfactory cognition of social relationships in Barbary macaques (Macaca sylvanus), an Old World monkey with sophisticated social relationships known to recognize individual attributes and social relationships using visual and auditory cues. We will employ a powerful, integrative approach that combines analysing the chemical composition of Barbary macaque scents with experimental presentations of conspecific scents. To do so, we will use state-of-the art, non-invasive sampling protocols, highly sensitive gas chromatography-mass spectrometry analysis and well-established cognitive test paradigms. In particular, we will determine which basic (identity, kinship, rank) and derived (third-party, group composition) social information can be obtained from the scents of Barbary macaques in two habituated, semi-free ranging populations living in naturalistic social settings. By relating the information contained in the composition of scents to the use of olfactory cues by monkeys for recognizing individual attributes and social relationships, the project will substantially contribute to understanding the olfactory mechanisms and cognitive underpinnings of managing social relationships as well as the evolution of primate communication and social complexity.