Laterality of Grooming and Tool Use in a Group of Captive Bonobos (Pan paniscus)

Abstract

Humans exhibit population level handedness for the right hand; however, the evolution of this behavioral phenotype is poorly understood. Here, we compared the laterality of a simple task (grooming) and a complex task (tool use) to investigate whether increasing task difficulty elicited individual hand preference among a group of captive bonobos (Pan paniscus). Subjects were 17 bonobos housed at the Columbus Zoo and Aquarium. Laterality of grooming was recorded using group scans; tool use was recorded using all-occurrence sampling. Grooming was characterized as unimanual or bimanual, and both tasks were scored as right-handed or left-handed. Most individuals did not exhibit significant hand preference for unimanual or bimanual (asymmetrical hand use) grooming, although 1 individual was lateralized for each. For the 8 subjects who engaged in termite fishing enough for statistical testing, 7 individuals exhibited significant laterality and strong individual hand preference. Four subjects preferred their left hand, 3 preferred their right, and 1 had no preference. Grooming, a simple behavior, was not lateralized in this group, yet a more complex behavior revealed a strong individual hand preference, and these results are congruent with other recent findings that demonstrate complex tasks elicit hand preference in bonobos.

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

“…In the last decades, studies evaluating hand preference in non‐human primates have increased greatly, both in captive and wild populations, and various authors suggested that a right hand bias at the population level does occur in non‐human primates (Hopkins et al, ; Humle & Matsuzawa, ; Llorente et al, ; Lonsdorf & Hopkins, ; Molesti, Vauclair, & Meguerditchian, ; Neufuss, Humle, Cremaschi, & Kivell, ; Poindexter, Reinhardt, Nijman, & Nekaris, in press; Regaiolli, Spiezio, & Hopkins, , 2018; Spinozzi, Castorina, & Truppa, ; Tabiowo & Forrester, ), but this right hand bias is not as strong and stable across different tasks as in humans (Cashmore, Uomini, & Chapelain, ; Marchant & McGrew, ). Other studies, however, with the same and different species report that lateralization in hand preference occurs only at an individual level (Brand et al, ; Leca, Gunst, & Huffman, ; Lilak & Phillips, ; Marchant & McGrew, ; Meunier & Vauclair, ; Papademetriou, Sheu, & Michel, ; Westergaard & Suomi, ).…”

Slow lorises (Nycticebusspp.) display evidence of handedness in the wild and in captivity

“…An HI of -1 represents a totally left-handed individual and an HI of +1 represents a totally right-handed individual. A one-sample binomial test for each slow loris in the unimanual reach and grasp task determined the significant bias in the use of the right or left hand (Brand, Marchant, Boose, White, Rood, & Meinelt, 2017). To analyse the unimanual task and spontaneous unimanual grasping at the group-level, we performed a one-Sample T-test on the distribution of the Absolute Handedness index (ABS-HI) with significance set to p < 0.05.…”

A comparative multimodal perspective on the evolutionary origins of tool use and handedness

“…For example, using a large sample size of chimpanzees, Hopkins and colleagues have consistently found that captive chimpanzees show a population-level right-hand bias for unimanual (e.g., reaching for food) and bimanual coordination tasks (e.g., tool use or solving the 'tube task' described below), as well as for communicative, manual gestures (Hopkins, Mareno, and Schapiro 2019;Hopkins, Russell, Freeman, et al 2005;Hopkins, Russell, Hook, et al 2005). However, many studies fail to find population-level biases in ape hand-use, including chimpanzees, even when employing similar methods (Brand et al 2017;Lambert 2012;Motes-Rodrigo, Hernandez-Aguilar, and Laska 2019;Prieur et al 2018) The significance of the corpus of captive research on primate handedness lies in its rich set of cross-species experiments whereby a standardized set of tasks and methods permits robust inferences. For example, a comparison of 777 captive great apes, including gorillas, bonobos, chim-Words, Bones, Genes, Tools: DFG Center for Advanced Studies panzees and orangutans found population-level right-hand bias in all apes for a bimanual coordinated task, excluding the orangutan (Hopkins et al 2011).…”