Hand Preference in Rhinopithecus roxellana Infants: Is It Influenced by Familial Inheritance?

The Sichuan snub-nosed monkey (Rhinopithecus roxellana) is a typical arboreal group-living Old-World primate and has been studied broadly in hand preference. However, infants have not been tested independently from other immature individuals to date. The purpose of the present study was to investigate hand preference in a spontaneously unimanual feeding task in nine infants at 12 months and the relationship of hand preference with their parents in R. roxellanae. Most infants (89%) showed individual-level hand preference. No correlation was found in the direction of hand preference between infant and its parents, and a significant negative correlation in the strength of hand preference was found between infants and their mothers (r = -0.715, p = 0.03). Moreover, there was no sex difference in the direction and strength of hand preference both in infants and adults (i.e., parents). Meanwhile, the strength of hand preference in adults was stronger than that in infants. This study is a first and preliminary exploration for the expression of hand preference in R. roxellanae infants and whether their hand preference was influenced by familial inheritance.