Collective decision-making and spatial patterns in orientation of an endemic ungulate on the Tibetan Plateau

Abstract

Group living animals form striking aggregation patterns and display synchronization, polarization, and collective intelligence. Though many collective behavioural studies have been conducted on small animals like insects and fish, research on large animals is still rare due to the limited availability of field collective data. We used drones to record videos and analysed the decision-making and behavioural spatial patterns in orientation of Kiang (Tibetan wild ass, Equus kiang). Leadership is unevenly distributed among Kiang, with the minority initiating majority behaviour-shift decisions. Decisions of individual to join are driven by imitation between group members, and are largely dependent on the number of members who have already joined. Kiang respond to the behaviour and position of neighbours through different strategies. They strongly polarize when moving, therefore adopting a linear alignment. When vigilant, orientation deviation increases as they form a tighter group. They remain scattered while feeding and, in that context, adopt a side-by-side alignment. This study reveals partially-shared decision-making among Kiang, whereby copying neighbours provides the wisdom to thrive in harsh conditions. This study also suggests that animals’ spatial patterns in orientation depend largely on their behavioural states in achieving synchronization.