Study On Co-maternal Behavior Of Female Captive Chinese Water Deer(Hydropotes Inermis)

Cooperative parenting for non-parental offspring occurs mostly in social animals such as primates,birds and insects,which is conducive to population continuation and stability.Will solitary animals cooperate in parenting under certain conditions?The Chinese water deer(Hydropotes inermis)is solitary in the wild,but forced to live in groups when they are captive.In the behavioral observation,we found the occurrence of the phenomenon of cooperative parenting among female deer,that is,female generally invest parenting care to non-parental fawn.In order to explore the pattern and benefits of the cooperative parenting in captive female,this study was carried out a captive group of Chinese water deer in the Huaxia Park,Pudong New Area,Shanghai.The parenting behaviors were observed by the focal animal sampling method and the whole-event recording method,then identification of the parentage of female and fawn using microsatellite marker technology,to analyze the female’s investment in parental and non-parental fawn and its impact on fawn.And use ELASA to measure the content of cortisol hormone in fawn hair and feces to understand the stress level of fawn at birth and in parenting.The results of the study are as follows1.The parental care of these two behaviors from female’s and the fawn’s getting have similar trends,higher in the first 4 weeks after birth,and gradually decreased in 5-8 weeks.Overall,the daytime lactating behavior and grooming were significantly correlated,accounting for 1.25±1.37%of the daytime(average daily frequency of 5.2±5.1 times)and 0.57±0.69%(average daily frequency of 6.2±5.7 times),respectively.For fawn,the daytime sucking and being groomed were also significantly correlated,accounting for 0.65%±0.51%(average daily frequency of 3.4±2.2 times)and 0.34±0.41%(average daily frequency of 3.0±3.6 times)of daytime time,respectively).2.During the observation period,the female deer had invested parental care in all non-parental fawn,took part of 61%of the total parental care,but the parental behaviors between matronage were relatively more frequent.The lactating behavior of female to parental fawn was 2.67 times of the average of nonparental young deer in duration and 3.45 times in frequency,and the grooming behavior of female to parental fawn was 2.56 times of non-parental fawn in duration and 2.46 times in frequency.Among them,the ratio of lactating behavior to parental and non-parental fawn was negatively and significantly correlated with the week age of fawn in duration(r=-0.721,p=0.044)and frequency(r=-0.664,p=0.042).The peak of the parental care between kinpair relationship between the parents was the closest,and after the 4th week,the female deer’s parenting input to the parent and non-parental fawn approached.3.Fawn begging to both parental and non-parental female.Overall,45.21%of the fawn’s begging was to its mother.The success rate of begging was similar between parental female(72.03%)and non-parental(75.30%)with no significant difference(p=0.528).4.Motherless fawns survived to weaning after being parented by other females.The motherless fawns got the lactating from other females(130.06±35.20h,82.5±14.85 times)was little higher than the other fawns(87.21±23.18h,65.25±8.38 times).As to being groomed,the total being groomed by nonparental female was similar to that of other fawns.5.There was no difference in hair cortisol detected among newborn fawn.And there was no significant difference in the stress level of fawns during lactation between motherless fawn and fawn with mother,which may due to all fawns got enough parental care for their survival and growth.The content of fecal cortisol metabolites was not significantly correlated with frequency of suckling(p=0.840),the success rate of begging(p=0.394),the frequency of being groomed(p=0.984),and sucking competition(p=0.509),which may be related to the fact that the overall investment in fawn in the cooperative parenting from female is similar(p=0.545),and a small sample size(n=48).To sum up,the female Chinese water deer have cooperative parenting under the condition of "living in group".Cooperative parenting helps the motherless fawn survived,which is beneficial to the maintenance and continuation of the population.the current data is not enough to support the difference in the stress level of the fawn caused by the difference care from parental or non-parental female.