ABSTRACT

Lateralization of hand use in primates has been extensively studied in a variety of contexts, and starts to be investigated in other species and organs in order to understand the evolution of the laterality according to different tasks. In elephants, the orientation of the movements of the trunk has been observed mainly in feeding and social contexts, in free conditions. However, little is known about the influence of task complexity on trunk laterality. In this study, we compared the lateralization of the trunk in two conditions: standardized and free. We offered granules to six African elephants on each side of an opened trapdoor to create a constraining environment and reported the different behaviours employed and their orientation. In addition, we observed the same individuals in free conditions and noted the lateralization of the use of their trunk. We revealed a common right side preference in all our elephants, both in standardized and free conditions. This side bias was stronger in our constraining task, adding evidence for the task complexity theory. We finally described laterality in new behaviours in the literature on elephants, such as pinching, gathering or exploration with the trunk.

摘要

灵长类动物手部使用的横向化已在各种背景下进行了广泛研究，并开始在其他物种和器官中进行研究，以了解根据不同任务的横向性演变。在大象身上，主要在自由条件下的摄食和社交环境中观察到象鼻运动的方向。然而，关于任务复杂性对躯干侧向性的影响知之甚少。在这项研究中，我们比较了两种情况下躯干的侧向化：标准化和自由。我们在打开的活板门的每一侧向六头非洲象提供颗粒，以创造一个约束环境，并报告所采用的不同行为及其方向。此外，我们在自由条件下观察了相同的个体，并注意到他们躯干使用的侧向化。我们揭示了我们所有大象的共同右侧偏好，无论是在标准化和自由条件下。这种偏向在我们的约束任务中更强，为任务复杂性理论增加了证据。我们最终描述了大象文献中新行为的侧向性，例如用鼻子捏、收集或探索。