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.

马匹开启扣合式门窗与围栏门的轶事报道，为探究马匹问题解决能力的潜在边界提供了富有启发性的研究路径。该物种的自然生存环境中，不存在与这类操控机制相似的情境。目前该主题的科学研究尚属空白，原因在于这类行为的发生频率过低，难以在可控条件下开展相关探索。
为此，我们从普通民众处收集了马匹打开闭合门窗与围栏门的案例报告。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素材，且对应案例中的马匹未表现出明显训练痕迹或福利受损的迹象。
本次数据集涵盖513例合页式门窗/围栏门、49例推拉门以及33例带栅门/通道的开启案例；涉及的操控机制包括260例横向栅杆、155例纵向栅杆、43例旋锁、42例门把手、34例电围栏把手、40例登山扣（carabiner），以及2例带钥匙的锁具。
马匹开启装置的动机通常为逃脱，亦可能为获取食物、接触厩伴，或是出于好奇与嬉戏心理。其中56%的马匹仅在单一地点开启单一类型的操控装置，另有44%的马匹可在不同地点（中位数为2，范围1~4）开启多种类型的操控装置（中位数为2，范围1~5）。
操控装置的复杂程度越高，马匹所需完成的动作次数越多，动作次数的中位数从门把手开启的2次，到登山扣开启的10次不等。需要通过头部或唇部扭转操作的装置，所需动作次数更多，且不同个体间存在显著差异。
问卷收录的案例中，74匹马有机会观察到厩伴的此类行为，其余183匹则无此条件；这表明后者要么是通过自主学习掌握了开启门窗与围栏门的技能，要么是通过观察人类学会了相关操作。
操作经验有助于提升开启效率：相较于仅能开启单一类型门窗装置的马匹，可开启多种装置的马匹单次解锁所需的动作次数更少。
我们未发现任何超出马匹学习能力范畴的门窗扣合装置复杂等级。因此，日常常用的所有装置，即便登山扣与电围栏把手，均存在被马匹开启的潜在风险，这一点在马匹安全饲养工作中需予以重视。