THE EFFECT OF BLOOD SIGNALS ON AGGRESSIVE-BEHAVIOR IN MICE

The study examined whether blood applied to the coal of a male opponen t mouse modifies the aggressive behaviour of the attacking male mouse. Interest was also focused on whether the signal value of blood is rel ated to the location of different bite targets, and whether such commu nication is visually or olfactorily mediated. The subjects used in the study were male Turku Aggressive (TA) mice of the 57th generation of selection for high levels of aggressiveness. The 72 TA males were divi ded into six groups matched on the times of latency to the first attac k in standard dyadic aggression tests. Different groups of male TA mic e were tested against opponents with blood, a red solution or nothing applied to either both flanks or the forehead. Testing was discontinue d after the first attack. The results showed that blood had an inhibit ing effect on aggression unrelated to the location of its application The opponents with blood applied to their coats were attacked signific antly later and the TA males sniffed such opponents significantly more . Odours associated with blood presumably serve as signalling pheromon es. The biological significance of blood signals is discussed. (C) 199 7 Elsevier Science B.V.