Heterogeneous bonds and relationships: uncovering the convergent evolutionary history between Golden snub-nosed monkeys with Homo sapiens.
by Yi-Jun Yang | Northwest University
Abstract ID: 122
Event: The 3rd AsiaEvo Conference
Topic: Behavioral evolution in vertebrates: diversity, genomics and mechanisms
Presenter Name: Yi-Jun Yang

Group living confers both benefits and challenges. Members in a group compete with one another in a variety of contexts from foraging, mating, and especially reproducing. As the key to group living, at least in primates, where individuals are truly connected (though in a variety of forms and degrees), cognitive abilities evolved for building and maintaining social networks. What are those cognitive abilities, and how do they help balance the costs and benefits of group living? Answering those questions helps unravel the myth of human evolution, as the evolution of shared intentionality, empathy, and sympathy provides the foundation of human uniqueness (e.g., complex societies, language, and culture).

We use a population of wild golden snub-nosed monkeys (Rhinopithecus roxellana) as the model of our comparative study. Our monkeys live in multi-level societies, where one-male units are nested in higher-level social organizations, including band, herd, and troop. Different social organizations serve different foraging or reproductive functions, and the highest level of organization is observable only when two herds temporarily fuse. As a result, social roles and relationships are heterogeneous and intricate, and both matrilineal and patrilineal kin are present, resembling human hunter-gatherer societies (e.g., the Hadza).

My past research aimed specifically at unraveling the nature of these relationships, using both behavioral and sociobiological approaches, and at uncovering the competitional and cooperative functions embedded in these relationships. In this presentation, I will present the two latest research of the team, one uncovering the intrasexual competition among same-unit females and the other revealing the role of contact calls in maintaining band cohesion (i.e., between one-male units). By presenting the two cases, I will confirm the existence of intense competition over reproductive and nutrient needs between and within units, as well as the evolved solutions that resolve conflicts and maintain a friendly atmosphere.

In addition, I will present the two ongoing research on our study population with the aim of specifying how individual differences are related to the differences in social and reproductive strategies, how individual differences predict fitness, and how vocalization and its combinations are used in different social contexts targeting different audiences.

Through the above topics, I want to give a comprehensive picture of the aims and scope of the golden snub-nosed monkey research group, as well as the ambition to uncover the convergent evolutionary history of social brain/cognition between Asian colobines with the Homo lineage.