兽类生态与进化（蒋学龙）知识库

人类群体水平的右利手是大脑偏侧性在行为上最明显的体现，研究非人灵长类的用手偏好性有助于探究人类大脑半球特化的起源与进化。2016年3月至9月期间对昆明动物园内17只圈养长臂猿进行了用手偏好性行为学研究。17只圈养长臂猿包括白眉长臂猿属6只和冠长臂猿属11只。研究采用焦点动物法，单次取样时长10min，对目标动物在不同圈养环境下进行分别采样，所有单手行为均记录所处姿势。出于样本量的考量，研究采用属内合并分析。通过对不同任务和情境下的利用手数据进行分析，验证手偏好相关理论，探究灵长类大脑功能偏侧性在情绪处理过程中的表现，并为圈养动物福利提供建议。白眉长臂猿和冠长臂猿在进食和食物搜寻两种自发单手行为中均存在个体水平的显著手偏好，但在不同任务之间的手偏好方向和强度并不稳定，稳定坐姿和扶吊姿势这两种姿势对手偏好没有显著影响，两种单手行为中均未发现群体水平手偏好的存在，不支持“姿势起源理论”。该结果与其他针对圈养长臂猿自发单手行为偏好性的研究结果一致。在自发双手合作复杂任务中，两属长臂猿都存在个体水平的手偏好，但未表现出群体水平的一致偏好性，不符合“复杂任务理论”，推测可能由于研究所选用的自发双手合作任务的难度在认知水平上尚未达到足够的复杂性。出生地因素对冠长臂猿自发双手合作汇总数据中的主导手偏好性具有显著影响，野外出生个体表现了一致的右手倾向性，而圈养环境下出生个体则表现一致的左手倾向性。自发单手行为对象的生命属性对两属长臂猿的手偏好无显著影响，但在稳定坐姿下的自发单手行为主要针对无生命对象，而在扶吊姿势下则主要针对有生命对象。白眉长臂猿在扶吊姿势下的同类导向行为中表现显著右手偏好，在稳定坐姿下的自我导向行为中表现显著左手偏好，由于同类和自我导向行为分别代表对积极和消极情绪刺激的反映，故白眉长臂猿大脑情绪处理过程符合“共价假说”。冠长臂猿在不同导向行为下的用手偏好性未达到显著水平。进食可显著降低圈养长臂猿的自我抓挠频率；雌性在低密度和高密度游客量参观下的自我抓挠频率均显著高于雄性；未成年个体在高密度游客量下的自我抓挠频率显著高于低密度游客量下的抓挠频率。圈养长臂猿在进食状态下倾向于使用右手抓挠身体右侧；随着游客量密度的增大，长臂猿开始更多的倾向于使用左手抓挠身体左侧，这种在不同情绪刺激影响下的抓挠利用手和抓挠体侧的倾向性符合“共价假说”。

The population level of right-handness in human is the hallmark of hemispheric specialization. Studying hand preference of primates could help us to understand the origin and evolution of cerebral hemisphere.The handedness study of captive gibbons in Kunming Zoo was conducted from March to September in 2016. The subjects were 17 individuals from two genera: Hoolock and Nomascas. Spontaneous manual behavior and subjects’ posture were collected by scan sampling at 5-min intervals in different cages. Through task-specific and context-specific analysis, the result could help to test theories in handness as well as emotive processing. Meanwhile, this study could also provide suggestions for the well-being of captive gibbons.Some individuals in both genera displayed an individual level of hand preference in unimanual tasks, however, the direction and strengh of handedness were not stable through tasks. Stable sitting posture and suspensory support posture have no influence on gibbons’ hand use. No population level hand preference was found in unimanual feeding or foraging tasks, which do not support the postural origin theory. Both hoolock gibbons and crested gibbons showed an individual level, but not population level of significant hand preference in coordianted bimanual tasks. The result was not in consist with the task complexity theory, which may caused by the lack of enough congitive demand of spontaneous bimanual tasks used in this study. Crested gibbons who was born in the wild showed a consistent trend of using right hand in all the coordinate bimanual tasks, whereas subjects born in zoo all use their left hand.Target animacy had no significant influence on the lateral hand use in neither hoolock gibbons nor crested gibbons. Unimanual behavior was mainly targeted to inanimate objects in stable sitting posture, meanwhile significantly more actions upon animate targets in suspensory support posture.Hoolock gibbons showed a right hand dominance through self-directed behavior and a left hand dominance to conspecific targets in suspensory support posture and stable sitting posture, respectively. Since conspeicific-directed and self-directed unimanual behavior were the reflection of positive and negative emotional stimuli, this result support the valence hypothesis of emotive processing. However, no significant interaction between hand use and different directed manual behavoir was found in crested gibbons.Self-scratch rates of captive gibbons decrease significantly in feeding context. Females scratched themselves significantly more frequent than males upon both low and high density of tourism. Juveniles had a significant higher level of scratch rates in high density of tourism compared with low tourist density. Although haven’t demonstrate to a significant level, captive gibbons did tend to ues right hand to scratch right side of body in feeding context; with the increase of tourism density, gibbons transferred to use their left hand scratching left body side. Our result in accordance with the valence hypothesis.