Between-task consistency, temporal stability and the role of posture in simple reach and fishing hand preference in chimpanzees (Pan troglodytes)

Studying hand preferences in chimpanzees can provide insights into the evolutionary origins of human hemispheric specialization. Research on chimpanzee preference requires careful examination important factors such as between-task consistency, temporal stability and posture although few studies have investigated all these combination. We simple reach fishing behaviours a group 19 at Chester Zoo UK. Simple was defined extending to grasp small object, then flexing limb continuous motion, examined quadrupedal, sitting climbing postures. Fish hole inserting stick wall with one extracting it same hand. Between-task consistency assessed by comparing fish hole, while from two points time: 2017 2019. The data showed no significant influence strength preference, which contrasts previous research. findings this study show reach, only partial consistency. Overall, results indicate that elicits laterality individual level is consistent across postures stable over time, literature. These suggest may be affecting preference. Further, whilst there overall time periods, some individuals changed their preferred hand, suggesting individual-level instability for certain tasks.