Patterns of dominance in the small scincid lizard Lampropholis guichenoti

We observed captive groups of six to ten scincid lizards (Lampropholis guichenoti) to investigate dominance patterns and to quantify and describe site defence. Most groups exhibited too few social interactions to determine social structure; however, in one group of nine L. guichenoti, a 'modified' despotic social structure was formed with two lizards dominant over all of the others. Body size and sex influenced position within the social structure, with males tending to dominate females and larger lizards tending to dominate smaller ones. In general males were more aggressive than females. A 'neck-arch' was used as the common assertion display and was seen significantly more frequently in males than females. Aggressive behavior did not decrease with time and thus may be involved in the maintenance of dominance as well as its establishment. Agonistic behavior resulting in displacement of lizards from basking or shelter sites was rare (observed in only one of 20 groups). When such behavior occurred, it generally consisted of displacement of smaller males by larger, more dominant males. Large males also tended to be found with females under shelter more often than were smaller males. The scarcity or absence of active site defence in L. guichenoti may be due to their small body size (and hence, the fact that suitable sites for basking and shelter are unlikely to be in short supply) and the apparent lack of fixed home ranges in this species.