On the basis of their dentition, species of Macropus are predicted to be grazers and species of Thylogale are predicted to be browsers. We tested these predictions by comparing diet and diet selection of the red-necked wallaby (Macropus rufogriseus rufogriseus) and red-bellied pademelon (Thylogale billardierii), by analysing forestomach contents of animals that had fed in the same region of a young pine plantation. Grasses, followed by broad-leafed forbs, were the most abundant plant groups in the field (together comprising 71% of the plant biomass), and were also the main dietary components of both macropodid species (91%). No differences were detected in diet of the two species when summarised in terms of diet diversity, evenness or overlap. When diet selection was compared, however, distinct differences were found between the two species. Red-necked wallabies selected for grasses (74% of the diet compared with 55% in the field) whereas red-bellied pademelons selected for broad-leafed forbs (38% of the diet compared with 16% in the field). Feeding patterns were therefore consistent with dietary predictions, provided diet selection was considered rather than simply diet. Diet selection is more appropriate for testing dietary predictions, because it reflects animals' attempts to consume food items that they prefer, that is, that they are functionally suited to consuming, even when such items are not as abundant as less preferred food.

The only specialized ant-eating mammal in Australia and New Guinea is the egg-laying short-beaked echidna (Tachyglossus aculeatus), and this single species occurs throughout Australia in a wide range of habitats. Despite the diversity of habitats and density and distribution of prey species, home-range sizes throughout Australia seem remarkably similar. We radiotracked echidnas in a population in Tasmania over a 13-year period and calculated home-range sizes using the fixed kernel method and the minimum convex polygon method. No relationship was found between body mass and home-range size, and mean annual home-range size of males (90% kernels) was 107 ha 6 48 SD, twice that of females (48 6 28 ha). Male home ranges overlapped considerably and also overlapped with those of several females. The echidna follows the pattern seen in many solitary eutherian mammals: both sexes are promiscuous, and males have larger home ranges than females. Echidnas show a high degree of home-range fidelity but can make rare excursions out of their normal area. Hibernating echidnas move between shelters during their periodic arousals, resulting in home-range sizes similar to those of the active period. Consistent with their very low metabolic rate, echidnas have home-range sizes considerably smaller than predicted for carnivorous or omnivorous mammals. Examination of data from other ant-eating mammals shows that as a group anteaters not only have smaller than predicted home ranges but they depart significantly from the normal relationship between home-range size and body mass.

The size of an animal’s home range is strongly influenced by the resources available within it. In productive, resource-rich habitats sufficient resources are obtainable within a smaller area, and for many species, home ranges are smaller in resource-rich habitats than in habitats with lower resource abundance. Location data on 14 male and 27 female echidnas (Tachyglossus aculeatus) fitted with tracking transmitters, in the southern midlands of Tasmania, were used to test the influence of habitat type on home-range size. We hypothesised that as woodland should offer more shelter, food resources and refuges than pasture, echidnas living in woodland would have smaller home ranges than those living in pasture areas. We found significant differences between the sexes. Male echidnas had a significantly larger mean home range than females and a quite different relationship between home-range size and habitat type from females. There was no relationship between the proportion of woodland within male home ranges and home-range size whereas female echidnas had a highly significant negative relationship. This suggests that home-range size of female echidnas is highly influenced by the amount of woodland within it, but the home-range size of male echidnas is controlled by factors other than habitat. This pattern is consistent with the spatial ecology of many other solitary species with a promiscuous mating system. The home ranges of females are scaled to encompass all necessary resources for successfully raising their young within a minimal area, whilst the large home ranges of males are scaled to maximise access to females.

The short-beaked echidna (Tachyglossus aculeatus) is generally considered to be myrmecophagous, consuming a diet consisting of ants and termites. The range and seasonal variation of food items consumed by echidnas in the Southern Midlands of Tasmania, an area where termites are absent, was examined using faecal scat analysis. Scat analysis indicated that echidnas in this region are not purely myrmecophagous. Whilst ants were present in 96% of scats and made up 55 ± 39% of scat contents by percentage volume, non-ant food items (scarab larvae and Oxycanus moth larvae) were found in 72% of scats. Scarab larvae were present in 68% of scats, and in those scats made up 46 ± 39% of the volume of prey material. The only significant seasonal variation of any dietary item was for scarab larvae, which can be attributed to variations in the abundance of these larvae throughout their lifecycle. The patterns of consumption indicate that echidnas are opportunistic foragers.

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