Territory acquisition in lizards: I. First encounters

Abstract

Abstract. Juvenile Anolis aeneus lizards were added to patches of microhabitat in the field and observed as they established territories. Here, the factors related to the type (fight versus chase) and the outcome (win, loss, draw) of first encounters between dyads during the settlement period are considered. The type of first encounters was influenced by relative body length, in that fights were more likely to occur if opponents were of similar size than if they were of disparate sizes. Another factor affecting the type of first encounters was the order in which individuals met novel opponents: juveniles were more likely to fight when encountering the first few opponents, but switched to chases after meeting several unfamiliar animals. The probability of winning a first encounter was affected by relative body size and relative familiarity, which was measured in terms of the amount of time each member of the dyad previously spent in the immediate vicinity of the first encounter. There was also an interaction between size and familiarity, indicating that juveniles tended to avoid first encounters that they were unlikely to win and conversely, to initiate first encounters when the odds of winning were more favourable.