Validation of a Noninvasive Hair Trapping Method for Extractive-Foraging Primates.

Hair is a useful source of biological information. For example, the bulb can be a source of high-quality genetic material, whereas the shaft can be useful for measuring heavy metals and some hormones, such as cortisol. The stable isotope composition of hair is another valuable source of biological information.

Young macaques (Macaca fascicularis) preferentially bias attention towards closer, older, and better tool users.

Examining how animals direct social learning during skill acquisition under natural conditions, generates data for examining hypotheses regarding how transmission biases influence cultural change in animal populations. We studied a population of macaques on Koram Island, Thailand, and examined model-based biases during interactions by unskilled individuals with tool-using group members. We first compared the prevalence of interactions (watching, obtaining food, object exploration) and proximity to tool users during interactions, in developing individuals (infants, juveniles) versus mature non-learners (adolescents, adults), to provide evidence that developing individuals are actively seeking information about tool use from social partners.

From play to proficiency: The ontogeny of stone-tool use in coastal-foraging long-tailed macaques (Macaca fascicularis) from a comparative perception-action perspective.

Macaques crack shellfish in coastal environments with specialized stone-hammering techniques. I provide the first examination of skill development from 866 object-manipulation and 7,400 tool-use bouts, collected over 15 months, using longitudinal analyses of infants' object manipulation (N = 7) and cross-sectional comparisons of manipulative and tool-use behavior (N = 69). I adopt a Perception-action approach, examining how the emergence of actions on objects relate to the spatial-relational and percussive challenges of tool use.

Complex processing of prickly pear cactus (Opuntia sp.) by free-ranging long-tailed macaques: preliminary analysis for hierarchical organisation.

Complex food-processing techniques by gorillas, chimpanzees, and orangutans have allowed comparisons of complex hierarchical cognition between great apes and humans. Here, we analyse preliminary observations of free-ranging long-tailed macaques (Macaca fascicularis) (n = 3) in Thailand processing Opuntia sp. cactus fruits.