Anxiety is a physio-psychological state anticipating an imminent threat. In social mammals it is behaviorally expressed via displacement activities and buffered via affiliation. Anxiety research on domestic pigs (Sus scrofa) has mostly focused on abnormal/stereotypic behavior associated with intensive farming. We investigated how anxiety is expressed and modulated in semi-free ranging pigs, in natural habitats. Owing to pigs' socio-cognitive complexity, we posited that displacement activities, if such, would increase after a (stressful) intra-group aggression (Prediction 1), be reduced by affiliation (Prediction 2) and influenced by individual/contextual factors (Prediction 3). From 224 videos recorded on adult individuals (Mean ± SD/subject: 4.84 ± 1.85 h) at the “Ethical Farm Parva Domus” (Turin, Italy), we extracted possible displacement activities (vacuum-chewing, scratching/body-rubbing, head/body-shaking, and yawning) in four 3-min conditions: before (BA) and after aggression events, in the absence (AA) or presence (AP) of post-aggression affiliation, and a matched-control (no event; MC). We conducted a minute-by-minute analysis in AE/AA and assessed the effect of subjects' involvement in a conflict (aggressor, aggression's recipient, bystander). All activities were higher in AA than in BA condition—thus being anxiety markers—and all of them decreased to baseline levels in AP, faster compared to AE. Hence, anxiety behavior in pigs was socially buffered. Intriguingly, anxiety behavior was expressed significantly more by bystanders than opponents, which suggests that pigs may be able to anticipate imminent threats. By highlighting how anxiety is managed under extensive farming, this study contributes to the understanding of pig welfare and biology.

焦虑是一种预期即将到来的威胁的生理心理状态。在社交哺乳动物中，它是行为表达的通过 流离失所活动和缓冲 通过联系。家猪的焦虑研究（猪cro）主要关注与集约化耕作有关的异常/陈规定型行为。我们研究了自然栖息地中半自由放养的猪中焦虑的表达和调控方式。由于猪的社会认知复杂性，我们假设，（如果这样的话）置换活动将在（紧张的）群体内攻击（预测1）之后增加，通过隶属关系（预测2）减少，并受个体/上下文因素的影响（预测3）。从“道德农场Parva Domus”（意大利都灵）的成年个体录制的224个视频中（平均±标清/对象：4.84±1.85 h），我们提取了可能的置换活动（真空咀嚼，刮擦/身体摩擦，头部/身体抖动， 和 打哈欠）在4个3分钟的条件下：侵略事件发生前（BA）和侵略事件后，侵略后隶属关系不存在（AA）或存在（AP）以及匹配控件（无事件； MC）。我们在AE / AA中进行了每分钟的分析，并评估了受试者卷入冲突（攻击者，攻击者，旁观者）的影响。在AA中，所有活动均高于在BA条件下的活动（因此是焦虑标记），并且所有活动均降低至AP的基线水平，比AE快。因此，猪的焦虑行为在社会上得到了缓冲。有趣的是，旁观者表达的焦虑行为明显多于对手，这表明猪也许能够预见到即将来临的威胁。通过强调在广泛的耕作下如何管理焦虑，这项研究有助于了解猪的福利和生物学。