The diet of the allied rock-wallaby, Petrogale assimilis, in the wet-dry tropics

Abstract

The diet of the allied rock-wallaby, Petrogale assimilis, an inhabitant of the wet-dry tropics of North Queensland, was studied over three years by microscopic faecal analysis, feeding observations, and an analysis of the ratios of the natural isotopes of 12*C and 13*C in the faeces. Forbs were the major food item, accounting for 22-65% of the identified epidermis in the faeces, and tended to be actively selected by the wallabies. Browse (20-41%) and plants with stellate trichomes (6-32%) were the next most-important dietary items, the latter being eaten in significantly higher proportions in the dry seasons of 1987 and 1988. Grass comprised only 5-16% of recognisable epidermis in the faeces, but was eaten in significantly higher proportions when fresh new growth was available. Forbs were difficult to identify at night, and most plants that rock-wallabies were recorded eating were those with stellate trichomes rather than forbs. The low incidence of grass in the diet was confirmed by the carbon-ratio analysis.