Tracking devices and methods for tracking

A tracking device comprising: a location determining means to determine a current location of a bearer; an activity monitor to determine physical characteristic of the bearer; and a transceiver configured to: send data related to the physical characteristic of the bearer obtained from the activity monitor to a remote server at predefined intervals; and activate the location determining means to determine the current location of the bearer when the transceiver determines that a request for location determination is received from a control device at the remote server. The bearer may be an animal, person, vehicle, or parcel; it may be a pet, with the device attached to its collar. The battery life of the tracking device is increased by monitoring physical characteristics (such as activity) continuously with a low power monitor and sending this data periodically, but only activating a higher power location determining means when it is needed.