Data_Sheet_1_Using Real-Time Kinematic (RTK) Devices to Show a Limited Effect of Boldness and Fearfulness on Social Proximity in Sheep Grazing at Pasture.PDF

Sheep are gregarious animals that can form close inter-individual relationships. Social bonds are affected by environmental and within-animal factors, but there is limited understanding of individual factors that influence social relationships, in part due to the challenges of accurately measuring individual social proximity within a group. This study used geospatially precise RTK-GNSS localization devices (Real-Time-Kinematic Global Navigation Satellite System) to evaluate social proximity between individuals with different personality traits in small sheep flocks. First, unsupervised clustering algorithms were used to categorize 78 individual Merino sheep (from a research flock of 108 grazed together for 11 months prior) based on their behavior measured in four behavioral tests: arena, novel object, flight speed, and isolation box. Sixty-five sheep were then categorized into five cohorts of 13 individuals each (clustered into three bold, six bold/fearful, and four fearful animals per cohort). Bold/fearful animals were bold toward a novel object but fearful of a human. Sheep within a single cohort were released into a 0.70 Ha test paddock with RTK-GNSS devices attached to their backs for 3 days to monitor relative positions. All cohorts were tested sequentially over a 5-week period. Social network analyses of GNSS locational data with a distance threshold of up to 30 m for all cohorts together showed no significant effect of personality traits (P = 0.11). There were, however, some significant but inconsistent differences in distances based on personality traits within separate cohorts [i.e., cohorts 1, 3, 4 (P ≤ 0.02), cohorts 2, 5 (P ≥ 0.44)]. When GNSS locational data were analyzed with a distance threshold of up to 2 m (day 2 excluded from all cohorts due to missing values), there was a significant effect of personality traits (P = 0.01) across all cohorts combined. The bold animals showed greater distances from each other relative to their distances from fearful or bold/fearful individuals. Additionally, regardless of personality traits, the average distance between animals decreased 2.2 m over the 3 test days. Social interactions in sheep flocks may be influenced by personality traits of fearfulness and boldness, but further research with larger numbers of sheep across varying environments is needed.

绵羊为群居动物，能够形成紧密的个体间关系。社会纽带受环境因素和动物自身因素的影响，然而，对于影响社会关系的个体因素的理解有限，部分原因在于准确测量群体内个体社会亲近度的挑战。本研究利用精确的地理空间RTK-GNSS定位设备（实时动态全球导航卫星系统）来评估小型羊群中具有不同性格特征的个体之间的社会亲近度。首先，采用无监督聚类算法根据在四个行为测试（场域、新奇物体、飞行速度和隔离箱）中测量的行为对78只美利奴绵羊（来自一个共同放牧11个月的研究羊群）进行分类。随后，65只绵羊被分为五个每组13个个体的群体（每个群体分为三个大胆型、六个大胆/恐惧型和四个恐惧型动物）。大胆/恐惧型动物对新奇物体表现出大胆的态度，但对人类表现出恐惧。单个群体内的绵羊被释放到0.70公顷的测试围栏中，其背部装有RTK-GNSS设备，以监测相对位置，持续3天。所有群体在5周内依次进行测试。对GNSS定位数据的社会网络分析显示，所有群体共同考虑的距离阈值为30米时，性格特征没有显著影响（P = 0.11）。然而，在单独的群体中，基于性格特征的距离差异显著但并不一致[例如，第1、3、4群体（P ≤ 0.02），第2、5群体（P ≥ 0.44）]。当GNSS定位数据以2米为距离阈值进行分析（由于缺失值，第2天所有群体均排除）时，所有群体综合来看，性格特征产生了显著影响（P = 0.01）。大胆型动物相对于恐惧型或大胆/恐惧型个体的距离，彼此之间的距离更远。此外，无论性格特征如何，动物之间的平均距离在3天的测试期间下降了2.2米。绵羊群中的社会互动可能受恐惧和大胆性格特征的影响，但需要进一步的研究，以更大数量的绵羊在多样化的环境中进行探索。