Abstract: Post-parturition infant rejection is common in captive chimpanzee. When this occurs, an immediate hand-rearing is required. Monitoring and observing the infant’s development and health status are essential for successful handrearing. Body weight serves as an important index of an individual’s growth and development and has been widely used in several mammalian species. However, there is currently no literature available on the changes in daily body weight gain in newborn chimpanzee infants. This study aimed to address this gap by monitoring and recording the changes in body weight during the first 12 months of life of six mother-rejected captive-born chimpanzee infants (2 females and 4 males) between 1999 and 2015 at Beijing Zoo and Dalian Forest Zoo. A linear regression model of weight-age was established based on the body weight data. A generalized linear model was then used to analyze the relationship between daily body weight gain and relative daily body weight gain and age by day, as well as to compare the two variables between two genders. The results showed that the body weight of chimpanzee infants increased linearly with age by day (y = 0.015 x + 2.139, R² = 0.830, P = 0.000 1), with females being significantly heavier than males of the same age by day (F = 10. 175, P < 0. 001). Both daily body weight gain and relative body weight gain decreased significantly with age by day (r = -0. 667, P = 0.035 and r = -0. 224, P = 0.042, respectively). The daily body weight gain and relative daily body weight gain in female infants were remarkably larger than those of males until they reached the ages of 235 and 184 days, respectively. Afterward, these two variables in female infants became smaller than those in male infants. Our results demonstrate sexual dimorphism in body weight, daily body weight gain and relative daily body weight gain of chimpanzees aged 0-12 months. These findings may provide a theoretical basis for increasing the survival rate of infants and enlarging the population size of chimpanzees in captivity.

Key words: Chimpanzee, Cubs, Body weight, Age in days, Gender difference

摘要： 圈养环境条件下黑猩猩产后弃婴频繁发生，此时需要人工哺育并对幼仔日常生长发育状况进行实时监测和评估。体重是反映个体生长发育和营养状况的一个重要指标。然而，有关婴幼黑猩猩体重变化规律的研究，迄今尚未见详细报道。本研究基于1999—2015年6只出生后遭遗弃转为人工育幼的黑猩猩幼仔(2雌4雄)在12月龄内体重的数据，首先建立了体重-日龄线性回归模型，然后以广义线性模型分析了幼仔体重变化与日龄的关系，比较了雌雄幼仔日增重与日增重率的差异。结果显示，黑猩猩幼仔的体重随日龄增长呈线性增加(y=0.015 x+2.139,R²=0.830,P=0.000 1)，同日龄的幼仔，雌性个体的体重显著大于雄性(F=10.175,P <0.001)；幼仔日增重和日增重率与其日龄呈显著负相关关系(日增重：r=-0.067,P=0.035；日增重率：r=-0.224,P=0.042)。在幼仔235日龄前，雌性的日增重显著大于雄性(F=1067.2,P=0.014)；在幼仔184日龄前，雌性的日增重率显著大于雄性(F=7.285,P < 0.001)。之后，雌性的上述两个指标均变为小于雄性。本研究结果表明：0~12月龄黑猩猩幼仔的体重、日增重和日增重率存在性二型性。该结果对圈养环境下婴幼黑猩猩的人工育幼具有一定的指导意义。

关键词: 黑猩猩, 幼仔, 体重, 日龄, 性别差异