Abstract: An animal information means which utilizes a region behind an animal's ear and adjacent its skull composed of skin, sub-cutaneous fascia and fat in which is formed a cavity, the temperature in the cavity being indicative of the animal's body temperature; the attachment including a temperature actuated warning assembly sensitive to a fever temperature in the animal, the warning assembly having a flanged end arranged to produce a conspicuous visual signal, the warning device being removably received and secured in a retainer assembly adapted to be inserted in the cavity, the retainer having an outer flanged end forming an exposed disk and an inner expansible end, the flanged and expansible end serving to clamp the fascia and skin surrounding the cavity; the retainer also being arranged to receive and secure a shield or guard underlying the flanged end of the retainer and projecting laterally beyond the warning assembly to prevent the surrounding hair growth from covering the warning device, the guard also servi