The Utilization of 'Eucalyptus' Foliage by the Greater Glider ('Petauroides volans') and the Brushtail Possum ('Trichosurus vulpecula')

Abstract

The utilization of 'Eucalyptus' foliage as a food source by Greater Gliders ('Petauroides volans') and Brushtail Possums ('Trichosurus vulpecula') was studied in captive animals fed diets of 'E. radiata' and 'E. melliodora' respectively. The rate of passage of solute (51Cr-EDTA) and particulate (103Ru-Phenanthroline) digesta markers was slow in both species. The mean retention time (MRT) of the two markers was 50h and 46h in the Greater Gliders and 51h and 46h in the Brushtail Possums. The lack of separation between these two markers was consistent with the lack of selective retention of fine particles in the hindgut of the Brushtail Possum. However, fine particles occurred in greater quantities in caecal digesta of the Greater Glider (48% DM) than in the stomach (30% DM) or faeces (16% DM). The rate of passage of an alternative particle marker (51Cr-mordanted large particles (<1.0mm>0.5mm)) in the Greater Gliders, was less than half that of 103Ru-P. From this it was concluded that 103Ru-P excretion reflected the excretion of fine digesta particles which were selectively retained in the caecum along with solute digesta. ... Efficient mastication and a relatively large hindgut, together with the selective retention of fine particles in the case of the Greater Glider, were important adaptations for utilizing 'Eucalyptus' foliage diets. However, it seemed unlikely that either marsupial species could survive solely on these single species diets in the wild unless they were able to substantially increase their intake of easily digestible nutrients.