An animal identification device (10) comprising: a metal ear tag (12) having a first part comprising a frame and a first mating portion (16) and a second part comprising a second mating portion (18) and a transponder housing (14) retained within the frame, wherein the first and second mating portions are locatable on opposite sides of an animals ear and engageable to connect the first and second parts. With this arrangement, the metal part of the ear tag is outermost, which can increase the durability of the ear tag, e.g. to allow it to be worn throughout the lifetime of the animal.
