title: Preliminary study on hand preference in captive northern white-cheeked gibbons (Nomascus leucogenys).
abstract: The postural origin hypothesis and the task complexity hypothesis propose that hand preference in non-human primates evolved in association with body posture and task complexity, respectively. The results of previous studies testing these two hypotheses, however, vary greatly with the different primate species and methods used. To investigate the effect of body posture and task complexity on hand preference, we recorded bouts of hand usage in nine captive northern white-cheeked gibbons (Nomascus leucogenys) housed at Beijing Zoo as they reached for food items in a ground-reaching task, a box task, and a tube task. The results showed that four to seven of the nine gibbons displayed a hand preference at the individual level in different tasks, and that hand preference in individuals was task-specific; there was no group-level hand preference in any task. The box task seemed to elicit a greater strength of hand preference than the ground-reaching task at the individual level. Although the small sample size rules out drawing any strong conclusions concerning hand preference at the group level, our results suggest that the suspensory reaching posture might increase the expression of hand preference at the individual level. This study provides preliminary information on hand preference in captive northern white-cheeked gibbons, and will be helpful for future studies addressing the origin and evolution of hand preference in small apes.
authors.affiliation: Ministry of Education, Key Laboratory of Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, People's Republic of China.
authors.forename: Penglai
authors.initials: P
authors.lastname: Fan
authors.affiliation: Ministry of Education, Key Laboratory of Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, People's Republic of China.
authors.forename: Chanyuan
authors.initials: C
authors.lastname: Liu
authors.affiliation: Ministry of Education, Key Laboratory of Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, People's Republic of China.
authors.forename: Hongyi
authors.initials: H
authors.lastname: Chen
authors.affiliation: Beijing Key Laboratory of Captive Wildlife Technologies in Beijing Zoo, Beijing, People's Republic of China.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Life Sciences, Tianjin Normal University, Tianjin, People's Republic of China.
authors.forename: Dapeng
authors.initials: D
authors.lastname: Zhao
authors.affiliation: Beijing Key Laboratory of Captive Wildlife Technologies in Beijing Zoo, Beijing, People's Republic of China.
authors.forename: Jinguo
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Ministry of Education, Key Laboratory of Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, People's Republic of China. dzliu@bnu.edu.cn.
authors.forename: Dingzhen
authors.identifier: http://orcid.org/0000-0002-1870-6197
authors.initials: D
authors.lastname: Liu
mesh_terms: D000818:Animals; D005260:Female; D007839:Functional Laterality; D006225:Hand; D016674:Hylobatidae / Q000502:physiology*; D008297:Male; D009043:Motor Activity; D011187:Posture
keywords: Manual laterality; Postural origin hypothesis; Suspensory reaching posture; Task complexity hypothesis