Hand Preference during Tool Use in Wild Bearded Capuchins

Abstract

The preferential use of one limb (lateralization) has been observed in many species. This lateralization reflects functional asymmetries of the brain. Right-handedness and left-hemisphere dominance seem to be the norm in humans. However, suggestions that vertebrates, particularly non-human primates, show handedness are contentious. Tool use could be a driver of handedness. Here I investigated hand bias during tool use activities in groups of wild capuchins (Sapajus libidinosus). I observed the use of feeding tools in wild capuchin monkeys living in the dry Caatinga forests of the Serra da Capivara National Park, Piaui, Brazil. Capuchins used three major types of feeding tools: (a) tools for probing; (b) tools for pounding/cracking, and (c) digging stones to extract tubers or roots. I recorded hand use in 118 tool use bouts. These different types of tools had different motor demands; digging tools apparently favour right-hand use. The harsh Caatinga habitat poses a strong selective pressure for tool using, which might favour increased laterality and right-hand bias. However, the extent of right-handedness associated with tool use, particularly for digging, can only be fully evaluated following studies with larger sample sizes.

Hand preferences and differences in extractive foraging in seven capuchin monkey species

“…Morphological data show that S. libidinosus is the most distinct among all robust capuchins, probably as a consequence of the unique selective factors in the Caatinga/Cerrado dry forest environment that has selected for greater reliance on terrestriality and the use of tools (Moura & Lee, ; Wright et al, ). Our data, however, suggest that tool use might not be a key driver for hand preference in Sapajus as previously suggested (Moura, ; Westergaard & Suomi, ).…”

“…Moreover, the manipulative complexity of extractive foraging seems to intensify during tool use, which requires diverse manual actions combined with strength, precision, bimanually coordinated movements, and more cognitive skills (Heldstab et al, ; Parker & Gibson, ; Resende, Nagy‐Reis, Lacerda, Pagnnota, & Savalli, ). Tool use is considered as a driver for right handedness (e.g., Forrester, Quaresmini, Leavens, Mareschal, & Thomas, ; Frost, ; Hopkins et al, ; Moura, ). Thus, we expected that S. libidinosus , a species that evolved in the dry forests of Brazil (Cerrado & Caatinga, Alfaro, Boubli, et al, ) should be more right handed.…”

“…Additional insights into the ecological forces driving hand preference differentiation among capuchin species can be gained through collection of more detailed behavioral and ecological data for each of the species. Unfortunately, there are just four studies evaluating hand preference in wild capuchins (Garber et al, ; Moura, ; Panger, ; Panger & Wolfe, ) and further studies in wild populations, particularly those from the Atlantic forest, are clearly needed. Our dataset on hand preference (Supplementary material Table S3) and further additional data could provide a stronger empirical framework for testing broad hypothesis on the selective pressures shaping the evolution of handedness.…”

Hand preference in wild crab‐eating capuchin monkeys (Sapajus libidinosus) in the coastal area of Northest Brazil

“…Most primate research on hand preference has been conducted on captive populations, with only a few but increasing studies testing wild primates (e.g., de A. Moura, 2015; Byrne & Byrne, 1991; Garber et al, 2008; Harrison & Byrne, 2000; Mittra et al, 1997; Panger, 1998; Panger & Wolfe, 2000; Salmi et al, 2016; Zhao et al, 2012). Some of the benefits of captive experimental research may include larger or more balanced sample sizes across sex and age categories, the ability to control for confounding factors, and the opportunity to test the same subjects across different tasks, all factors that have greatly improved our understanding of the effects of development, task complexity, postural constraints, and neuroanatomical asymmetries, among others, on hand preference (e.g., Anderson et al, 1996; Hopkins, 2018; Hopkins & Bard, 1993; Mangalam et al, 2015; Phillips & Thompson, 2013; Stone & Gonzalez, 2015).…”

Hand preference in unimanual and bimanual coordinated tasks in wild western lowland gorillas (Gorilla gorilla gorilla) feeding on African ginger (Zingiberaceae)

“…There tends to be more evidence of population-level right-hand preference for bimanual coordinated tasks than for tool-use (Cashmore et al, 2008). However, there is a continuing debate about which factor is important for the evolution of population-level righthandedness in humans: tool-use (e.g., Braccini et al, 2010;Hopkins et al, 2017;Moura, 2015;Uomini, 2009) or bimanual coordinated tasks (e.g., Chapelain & Hogervorst, 2009;de Andrade & de Sousa, 2018;Meguerditchian et al, 2010Meguerditchian et al, , 2013Salmi et al, 2016). In this regard, further evidence of hand preference in gorillas may be important because gorillas do not customarily use tools (but see Breuer et al, 2005;Kinani & Zimmerman, 2015), but often demonstrate bimanual coordinated feeding in the wild.…”