Abstract: The biting ability of giant pandas (Ailuropoda melanoleuca) holds significant importance in terms of food acquisition and male-male competition. Their distinctive dietary preferences and masticatory system render them an ideal species for investigating bite forces. Nevertheless, current studies have predominantly relied on theoretical assessments derived from panda skull morphology, with no empirical animal experimentation conducted. The present study designed a force transducer specifically tailored for giant pandas, and measured body weight, bite forces, and feeding rate in a sample of 46 individuals from various age groups, with a particular focus on juvenile development. The results showed that bite forces at the tip of the incisor of juvenile giant pandas increased rapidly during the dental transitional period, as well as the feeding rate of bamboo shoots. At the end of the dental transitional phase, the bite forces exerted at the incisor point of juvenile giant pandas continued to display a growing trend, albeit at a decelerated rate. Concurrently, the feeding rate reached a state of equilibrium. The utilization of a logistic model revealed that age explains 87.56% of the variance observed in the feeding rate among juvenile pandas. As for the comparisons of age groups, the median bite force value exhibited an upward trajectory in tandem with increasing age. The bite force of 8-month to 12-month age group was significantly lower than the bite forces of all the other age groups; the bite force of 13-month to 18-month age group was significantly lower than those of sub-adult, adults and geriatric group; however, there was no significant difference between the latter three groups. The adult group has the highest feeding rate of bamboo shoots and carrots, followed successively by the sub-adult group, the geriatric groups and the juvenile group. In summary, our study confirmed for the first time the feasibility of measuring bite forces of giant pandas by using force transducer, recorded the developmental process of bite forces and feeding rate of juvenile giant pandas during the dental transitional period, and discussed the effect of age on bite forces and feeding rate, all of which laying a good foundation for future work of giant pandas’ feeding ecology.

Key words: Giant panda, Bite forces, Feeding rate, Age groups, Dental transitional period

摘要： 咬合力在食物获取和雄性竞争等多方面影响大熊猫的生存和繁殖，同时，食性和咀嚼系统的独特性使大熊猫 (Ailuropoda melanoleuca) 成为研究咬合力的理想物种。以往研究仅局限在通过测量大熊猫头骨进行力学模型估测，未经实体测量验证。本研究采用测力传感器定量测量了不同年龄段 46 只大熊猫的体重、切齿咬合力和采食速率，并重点关注幼仔期的发育过程。结果显示：幼年大熊猫的切齿咬合力在切齿由乳齿到恒齿的过渡期呈较快速度的增长，与此同时，采食竹笋的速率也呈快速上升趋势；在全部切齿更换为恒齿后，其切齿咬合力仍然呈上升趋势，但速度变缓，而采食速率进入平台期。经 Logistics 模型对采食速率增长曲线拟合，表明月龄可以解释速率变异的 87. 56%。不同年龄阶段的大熊猫咬合力中位数随年龄呈现明显的增长趋势，8 ~ 12月龄组的咬合力显著小于其他年龄组，13 ~ 18月龄的咬合力显著小于亚成年组、成年组以及老年组；亚成年组、成年组和老年组间尚未检测出显著性差异。竹笋和胡萝卜的采食速率以成年大熊猫最高，亚成年次之，老年略低于亚成年，幼年最低。本研究验证了测力传感器测量大熊猫咬合力的可行性，记录了咬合力和采食速率在幼年大熊猫换牙期的变化过程，并探讨了年龄与咬合力和采食速率的关系，为以后进一步的研究奠定基础。

关键词: 大熊猫, 咬合力, 采食速率, 年龄组, 换牙期