Individual leadership in cattle persists when collective movement is induced by robotic herding
In social species, some individuals consistently lead collective movements while others follow, but whether these roles persist when movement is externally induced remains unknown. Robotic herding offers a way to address this: animals are displaced by an approaching device, yet retain the option to stay, to move or to follow a conspecific that has moved. We recorded spontaneous group departures in a herd of 18 Japanese Black cows on three days, then recorded which individuals initiated movement away from a quadruped robot, which followed and which remained, across an eight-day herding trial. Cows that frequently initiated spontaneous departures and attracted followers also initiated movement away from the robot more often and drew more followers, whereas habitual followers tended to be less effective initiators. Follower frequency during herding was unrelated to any characteristic measured. Individual leadership therefore persists when movement is induced by a robot. Behavioural roles may thus be expressed under moderate external constraint, provided animals retain some freedom of choice. Identifying leaders from spontaneous departures offers a practical route to more efficient robotic herding.