Collar stud (14) that can be attached to an animal collar (12) to function as a tag, collar lock, and/or electronic identification device. The stud (14) includes a cap (32) positionable adjacent an exterior (34) of the collar (12) and a base (36) that is positionable adjacent an interior surface (38) of the collar (12). A linkage (40) interconnects the cap (32) and base (36) in a spaced apart fashion to allow a portion of the collar (12) to be sandwiched between the interconnected cap (32) and base (36). At least a portion of the linkage (40) extends through an aperture (30) of the collar portion (12) and helps secure the stud (14) to the collar portion (12). A transponder (58) is preferably incorporated into the stud (14), wherein the transponder (58) includes a memory storing retrievable information comprising an identification code. The code can be used to access a corresponding data record in a database.