The auricular livestock identification tag comprising a male portion having a head at an end of a narrower stem, the head protruding laterally from the stem by an abutment ledge, and a female portion having an annular body with an axial aperture, and an insertion side opposite an exposure side, and a plurality of resilient abutment members extending inwardly from the annular body into the axial aperture, the abutment members being flexible to allow penetration of the head through the axial aperture from the insertion side to the exposure side, and resilient so as to return toward its original position, and under the abutment ledge, after said penetration, to thereafter prevent retraction of the head through the axial aperture.