An apparatus for the virtual fencing of an animal is provided which includes a microprocessor for continuously determining the position of an animal relative to a target and to determine whether the animal is moving relative to the target. The apparatus further includes a stimulus unit for applying a sensory stimulus to the animal in response to signals received from the microprocessor. The microprocessor is programmable such that if the distance between the animal and the target is less than a predetermined distance and if the animal is moving in a direction towards the target a stimulus is applied to the animal and the stimulus is withdrawn when the animal either stops, retreats from the target, or accelerates whilst the distance between the animal and the target is less than the predetermined distance. In addition a method for the virtual fencing of an animal is provided. The method includes determining the position of an animal relative to a target and whether the animal is moving relative to the target, calculating a distance between the animal and the target, applying a stimulus to the animal if the distance between the animal and the target is less than a predetermined distance and if the animal is moving in a direction towards the target and withdrawing the application of the stimulus to the animal when the animal either stops, retreats from the target, or accelerates.Linvention concerne un appareil permettant de clôturer virtuellement un animal et comprenant un microprocesseur permettant de déterminer en continu la position dun animal par rapport à une cible et de déterminer si lanimal se déplace par rapport à la cible. Lappareil comprend également une unité de stimulus permettant dappliquer un stimulus sensoriel sur lanimal, en réponse à des signaux reçus du microprocesseur. Celui-ci est programmable de manière que, si la distance entre lanimal et la cible est inférieure à une distance prédéterminée et si lanimal se déplace en direction de la cible, un sti
