Disclosed is an animal tracking device, which is worn by an animal and tracks a location of the animal, the animal tracking device including: a location determining unit configured to determine a current location according to information received from a GPS antenna； a sensor configured to determine state information about the animal； a device identification information storing unit configured to store device identification information for identifying a device； a battery configured to supply power； a first communication unit configured to perform RF communication with a user's device； and a main control unit, which controls the device, and controls the first communication unit to communicate with the user's device through another animal tracking device registered in the user's device, and a system including the same and a method of tracking a location of an animal.
