MORPHOLOGICAL AND BEHAVIORAL TRAITS AFFECTING THE INTENSITY AND OUTCOME OF MALE CONTESTS IN GALLOTIA-GALLOTI GALLOTI (FAMILY LACERTIDAE)

This study describes the sequence of behaviour during aggressive encou nters between male 'tizon' lizards (G. galloti galloti) and assesses t he effect of morphological and behavioural traits on the outcome and i ntensity of staged aggressive encounters between males. Aggressive enc ounters ranged from only throat extension to escalated fights with bit ing and rolling over. winners were heavier. had longer heads, and perf ormed tongue-flicking, throat extension and biting at a higher rate th an losers. The rate of aggressive behaviour increased with decreasing difference in snout-to-vent length, head length and head width of the contestants. The results are in agreement with some predictions of the sequential assessment game model in that probability of victory incre ased with the difference in lighting ability and that the rate of aggr essive behaviour was higher in contests between animals of similar siz e.