Animal behaviour in a human world: A crowdsourcing study on horses that open door and gate mechanisms

Anecdotal reports of horses opening fastened doors and gates are an intriguing way of exploring the possible scope of horses’ problem-solving capacities. The species’ natural environment has no analogues of the mechanisms involved. Scientific studies on the topic are missing, because the rate of occurrence is too low for exploration under controlled conditions. Therefore, we compiled from lay persons case reports of horses opening closed doors and gates. Additionally, we collected video documentations at the internet platform YouTube, taking care to select raw data footage of unedited, clearly described and clearly visible cases of animals with no distinct signs of training or reduced welfare. The data included individuals opening 513 doors or gates on hinges, 49 sliding doors, and 33 barred doors and gateways; mechanisms included 260 cases of horizontal and 155 vertical bars, 43 twist locks, 42 door handles, 34 electric fence handles, 40 carabiners, and 2 locks with keys. Opening was usually for escape, but also for access to food or stable-mates, or out of curiosity or playfulness. While 56 percent of the horses opened a single mechanism at one location, 44 percent opened several types of mechanism (median = 2, min. = 1, max. = 5) at different locations (median = 2, min. = 1, max. = 4). The more complex the mechanism was, the more movements were applied, varying from median 2 for door handles to 10 for carabiners. Mechanisms requiring head- or lip-twisting needed more movements, with significant variation between individuals. 74 horses reported in the questionnaire had options for observing the behaviour in stable mates, 183 did not, which indicates that the latter learned to open doors and gates either individually or from observing humans. Experience favours opening efficiency; subjects which opened several door types applied fewer movements per lock than horses which opened only one door type. We failed to identify a level of complexity of door-fastening mechanism that was beyond the learning capacity of the horse to open. Thus, all devices in frequent use, even carabiners and electric fence handles, are potentially vulnerable to opening by horses, something which needs to be considered in relation to keeping horses safely.

马匹开启紧固门窗与围栏的轶事报道，为探究马匹的问题解决能力边界提供了颇具吸引力的研究路径。该物种的自然栖息环境中，并不存在与之相关的机械结构类似物。由于这类事件的发生频率过低，难以在可控条件下开展研究，因此目前该主题尚未有科学研究问世。为此，我们从普通民众提交的马匹开启闭合门窗与围栏的案例报告中整理收集数据；此外，我们从视频平台YouTube上收集了相关影像资料，严格筛选未经剪辑、描述清晰且画面可明确辨识的案例素材，且这些案例中的马匹未表现出明显的训练痕迹或福利受损迹象。本次收集的数据涵盖：513起马匹开启合页式门窗/围栏、49起推拉门、33起栅格式门窗/围栏的案例；涉及的机械结构包括260起横栅结构、155起竖栅结构、43起旋转锁、42起门把手、34起电围栏把手、40起登山扣（carabiners）以及2起带钥匙的锁具案例。马匹开启这些装置的动机通常为逃离，也有为获取食物、接触同厩同伴，或是出于好奇与嬉戏。其中56%的马匹仅在单一位置开启单一种类的机械结构，44%的马匹可在不同位置开启多种类结构（中位数为2，最小值为1，最大值为5），涉及的位置数量中位数为2，最小值为1，最大值为4。机械结构越复杂，马匹所需完成的动作次数越多，动作次数中位数从门把手对应的2次到登山扣对应的10次不等。需要通过头部或唇部扭动操作的结构，所需动作次数更多，且不同个体间存在显著差异。在问卷报告的案例中，74起案例的马匹有观察同厩同伴开启行为的机会，183起则无此条件，这表明后者要么是通过自主学习，要么是通过观察人类学会了开启门窗与围栏。实践经验有助于提升开启效率：能够开启多种门窗结构的马匹，单个锁具所需的平均动作次数少于仅能开启单一种类结构的马匹。我们未发现任何复杂程度超出马匹学习开启能力的门窗紧固结构。因此，所有日常常用的装置，即便登山扣与电围栏把手，都有可能被马匹开启，这一点在马匹安全饲养管理中需予以重视。