In a tag for identifying and marking animals, the tag associates a receiver button (1) by irreversible fitting of a finger (2). The button (1) includes a head (13) wherein is provided a cavity (8) for receiving a punch (3) of the finger (2). The head (13) is secured to a shell (5) retaining the punch (3) which is provided with an opening (6) for introducing the punch (3) inside the button (1). The axial wall (7) of the retaining shell (5) delimiting the opening (6) is radially deformable. A chamber (11) is arranged between the head (13) and the axial wall (7) for receiving the latter (7) deformed under the effect of the punch (3) passing through the opening (6).