The Study Of Allomaternal Behavior Of Golden Snub-nosed Monkeys(Rhinopithecus Roxellana)in Shennongjia National Park,China

In non-human primates,in addition to mothers,other non-maternal individuals in the group also take care of infant.Detailed observations of allomaternal behaviors are critical for clearly understanding the maternal benefit and influencing factors of allomaternal behaviors in Rhinopithecus roxellana.golden snub-nosed monkeys,which belongs to the subfamily Ceratopterinae,is an endangered species endemic to China.It has the characteristics of living in clusters and special multilevel society.It is an ideal research object to explore the influencing factors and mechanism of allomaternal behavior in the complex society of primates.From March to November 2019,the allomaternal behaviors of infants aged 0-6 months was observed with objective animal sampling and scanning sampling methods at Dalongtan,in Shennongjia National Park,China.10 mother-infant dyads from five one-male units were chosen as our focal subjects and observed each infant from the time that it was born to the day they were 6 months old.The total of observation time was 165 hours and allomaternal behavior time was 30 hours.Our study findings were summarized below:(1)On the first day after birth,those infants were cared for by non-mothers.According to the time proportion,the type of allomaternal behavior were holding behavior,touching behavior,grooming behavior,nursing behavior and carrying behavior.(2)The non-maternal care time was negatively correlated with the infant monkey age.The time adult male spent in allomaternal behaviors was significantly positively correlated with infant age,while adult female and juvenile were significantly negatively correlated.The gender and reproductive experience of non-maternal caregivers had a significant influence on the non-maternal care time and care type,while the sex and birth date of infants had a minimal influence on non-maternal behavior.The gender had no significant effect on the non-maternal care time.(3)When infants were cared for by mother,the mother's activities were mainly rest and grooming,and hardly movement with infant;When infants were cared for by non-maternal caregivers,the mothers' feeding and grooming time significantly increased,and the rest time decreased significantly.In general,the time non-maternal caregivers spent in allomaternal behaviors was significantly negatively correlated with infant age.The gender and reproductive experience of non-maternal caregivers had a significant influence,while the sex and birth date of infants had a minimal influence on non-maternal behavior.When infants were cared for by non-maternal caregivers,the mothers'feeding and grooming time significantly increased.Therefore,mothers' benefit from allomaternal behavior via gaining more time for feeding and grooming,to increase feeding efficiency and meet their hygiene and social needs.In addition,juveniles with no reproductive experience learn the reproductive experience.The results support two major hypotheses,i.e.those of learning-to-mother hypothesis and maernal relief hypothesis.