Grazing cattle respond more strongly to a quadruped robot than to a drone but habituate over consecutive days

Robots are increasingly used to manage animals, but whether animals keep responding to robots over repeated encounters is poorly understood. Habituation theory predicts that more salient stimuli elicit stronger responses and habituate more slowly, and that responses recover partially after a pause in stimulation, followed by faster habituation. We tested these predictions in a field study of robotic herding of grazing Japanese Black cattle, Bos taurus. We compared the responses of 22 cows to a drone and to a quadruped robot, each playing either dog barking or an air horn (266 approach events), and herded 24 cows with the robot on five consecutive days in September and three consecutive days in October, after a 24-day interruption (823 approach events). Binomial generalized linear mixed models with cow identity as a random effect showed that the odds of moving away from the device were twice as high for the robot as for the drone, the odds of showing no response were six times lower and the odds of flight were four times higher; the acoustic stimulus had no main effect on any response. Herding succeeded more often with the robot, particularly when it played dog barking. During consecutive herding with the robot, the odds of moving away and of flight declined by approximately 30% per day in September, responses partially recovered after the interruption, and the decline in October was steeper than in September for flight. Fear-related responses occurred in fewer than 5% of approach events, and cows differed consistently in their responsiveness. Our results show that a ground-level, dog-like robot is a more salient stimulus for cattle than a drone, but its effect still wanes with repeated exposure, in line with the characteristics of habituation described in laboratory studies. Managing habituation will therefore be essential for sustained robotic herding.