Asymmetric interactions in infant handling during the first 12 weeks after infants’ birth in wild Japanese macaques

Abstract

Infant Japanese macaques living in Yakushima (Macaca fuscata yakui) are gently handled as usual. Infants tend not to show rejection toward those gentle handlings and sometimes approach or physically contact the handlers. In contrast to this general trend, we found asymmetric interactions according infants’ developmental stages. some handlings make infants squirm, squawk and cry. Over half of them tend not to be stopped even after the infants’ obvious negative responses, which make infants more panicky. Those excessive handlings are found when infants are around 2 months old the most frequently, when infants become to have more developed locomotion abilities. This study has investigated the patterns of the excessive handlings and their relationship with infants’ physical development during the first 12 weeks after birth.