This study investigated the relationship between chronological age and social behavior in 42 adult male and female rhesus macaques (Macaca mulatta) in three specific areas: social interactions, social roles, and social networks. While both old males and old females share behavioral differences associated with senescence, this study reports that old females and old males are distinct in their so...

The identification of early markers that predict the development of specific social trajectories is critical to understand the developmental and neurobiological underpinnings of healthy social development. We investigated, in infant rhesus macaques (Macaca mulatta), whether newborns' capacity to imitate facial gestures is a valid predictive marker for the emergence of social competencies later ...

Self-recognition in front of a mirror is used as an indicator of self-awareness. Along with humans, some chimpanzees and orangutans have been shown to be self-aware using the mark test. Monkeys are conspicuously absent from this list because they fail the mark test and show persistent signs of social responses to mirrors despite prolonged exposure, which has been interpreted as evidence of a co...

This study investigated lateral biases in nipple preferences, maternal cradling, carrying, and retrieval in 41 rhesus macaque (Macaca mulatta) mother-infant dyads living in two captive social groups. Observations were made during the first 6 weeks of infant life using a combination of scan sampling and ad-libitum sampling techniques. Infants exhibited a significant left-nipple preference in the...

Rotational displacement tasks, in which participants must track an object at a hiding location within an array while the array rotates, exhibit a puzzling developmental pattern in humans. Human children take an unusually long time to master this task and tend to solve rotational problems through the use of nongeometric features or landmarks as opposed to other kinds of spatial cues. We investig...

Kin recognition can enhance inclusive fitness via nepotism and optimal outbreeding. Mechanisms allowing recognition of patrilineal relatives are of particular interest in species in which females mate promiscuously, leading to paternity uncertainty. Humans are known to detect facial similarities between kin in the faces of third parties, and there is some evidence for continuity of this ability...

Abstract Background Understanding the rate and pattern of germline mutations is fundamental importance for understanding evolutionary processes. Results Here we analyzed 19 parent-offspring trios rhesus macaques (Macaca mulatta) at high sequencing coverage ?76× per individual estimated a mean 0.77 × 10?8de novo site generation (95% CI: 0.69 10?8 to 0.85 10?8). By phasing 50% parental origins, f...