An animal monitoring system, comprising a proximity sensor arrangement comprising a first part 3 and a second part 2 and operable to detect instances of proximity between the first part and the second part. The first part 3 of the proximity sensor arrangement is configured to be attached to or implanted into an animal, and the proximity sensor arrangement is operable to generate proximity data upon detecting an instance of proximity between the first part and the second part. The first part 3 of the proximity sensor may be a pet worn device such as a collar, and the second part 2 of the proximity sensor may be a beacon associated with a monitored location and/or resource, such as a food bowl, water bowl, flap or exercise yard. The first part 3 may include sensors to monitor the ambient temperature or the movement of the animal. The information may be used to monitor overall activity and help to identify any health issues with a pet. The proximity and sensor information may be transmitted by the pet worn devic
