Coalitions in male sugar gliders: are they natural?

The sugar glider Petaurus breviceps is generally considered to be a polygyn ous, group-nesting species. However, recent captive studies have indicated that dominance hierarchies and shared codominance amongst males formed when males were housed in multiple-male, multiple-female cages with male-biased sex ratios. This study uses data from sugar glider groups in natural popul ations to assess the probability of male dominance hierarchies and the oppo rtunity for codominant father-son coalitions. Nesting groups of sugar glide rs were found to have female-biased sex ratios ranging from 1:1.5 to 1:2.7 males:females. The dispersing sex was male - there were four records of rec ruitment into the natal group, all of which were female. Only one example w as found of a long-term adult male association between a father and putativ e son, which did not occur in the natal group of the son. The evidence sugg ests that though father-son associations may occur, the opportunities for m ale dominance hierarchies or male coalitions are rare in sugar glider nesti ng groups in the natural environment.