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The nearly universal right hand preference manifested by human populations is one of the most pronounced manifestations of population-level lateralization. Morphological and archeological evidence indicate that this behavioral specialization may have emerged among our hominin ancestors. Whether population-level behavioral asymmetries are evident in non-human animals remains a topic of considerable scientific debate, with the most consistent evidence of population-level trends emerging from studies of chimpanzees ( Pan troglodytes). However, previous studies of population-level lateralization in wild apes have relied upon data sets pooled across populations to reach adequate sample sizes. Our aim was to test for population-level handedness within a single wild chimpanzee population, and also to determine if performance asymmetries were associated with handedness. To address these questions, we coded handedness and duration of fishing probe insertions from remote video footage of chimpanzee visitation to termite nests (totaling 119 hr) in the Goualougo Triangle, Republic of Congo. Similar to reports from other populations, chimpanzees in the Goualougo Triangle showed robust individual hand preferences for termite fishing. There were 46 right-handed, 39 left-handed, and 4 ambiguously-handed individuals. Though we did not detect an overall significant population-level handedness ( t(88) = 0.83, n.s.) in this study, males showed a greater right hand preference than females. Further, we found that average dipping latencies were significantly faster for right- compared to left-handed chimpanzees. Possible explanations and evolutionary implications of taxa- and task-specific patterns of population-level laterality are discussed. Am. J. Primatol. 78:1190-1200, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

ABSTRACT Studies of chimpanzee termite foraging enlighten our understanding of early hominin tool use not only by modeling the cognitive ability of our ancestors but also by emphasizing the possible role of social insects in the hominin diet. The chimpanzees of the Goualougo Triangle are known to have one of the largest and most complex tool repertoires reported for wild chimpanzees. One tool set habitually used by this population includes a perforating tool to penetrate the hard outer crust of elevated termite nests before fishing for termite prey with an herbaceous stem. Here, we report the variation present in the grips used on the perforating tool. Our analysis of video recordings of chimpanzee visitation to termite nests over a 3-year period shows that these chimpanzees use a variety of grips to navigate the challenges encountered in opening a termite nest. For situations in which the soil is most hardened, perforating requires force and a power grip is often used. When the soil in the passageway is loose, precision grips are suitable for the task. One of the preferred grips reported here is an interdigital brace, which has previously been described in studies of how some people hold a pencil. In this study, for the first time, the interdigital brace has been thoroughly described for chimpanzees. The various strategies and grips used during perforation emphasize the importance of termites as a nutritional resource that should be considered more strongly as a food used by early hominins. Am J Phys Anthropol 157:252-259, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]