Stress and sociality in a patrilocal primate: Do female spider monkeys tend and befriend?

Welcome to my dissertation research! I defended my proposal last week, and I realize I haven't shared too much about my project yet. So, for starters, here's the abstract from my proposal!

Stress is an adaptive strategy that mobilizes the body for acute physical challenges. However, chronic stress has detrimental effects that can reduce health and reproductive fitness. Thus, coping mechanisms are valuable in reducing chronic stress. One such mechanism, the “tend-and-befriend” strategy, refers to affiliation between females as an adaptive strategy to deal with stress. This mechanism is proposed to be a widespread strategy throughout the primate order, and one that underlies patterns of female bonding in humans. Although this strategy has been documented in matrilineal primates characterized by female kinship bonds, there has not been documentation of this strategy among unrelated females. Such documentation is necessary to demonstrate that this strategy is unrelated to female philopatry. Since our hominid ancestors are presumed to be male-philopatric, examining if this strategy applies to unrelated females is essential to understanding the evolutionary context of this mechanism. Here, I propose to examine the tend-and-befriend strategy in a species characterized by fission-fusion social organization and female dispersal. I will examine the patterns of female-female social relationships, male aggression, and ecological variables on glucocorticoid concentrations, a measure of physiological stress, among female black-handed spider monkeys. I predict that strong female social relationships, regardless of relatedness, will be associated with low glucocorticoid levels. Behavioral, hormonal, genetic, and ecological data will be collected in a wild, habituated community. This research has direct implications for understanding the evolution of the stress-response, and whether bonding among unrelated females is a result of ancestral tendencies within the primate order or a more derived feature limited to certain taxa.