Digestion and energy metabolism in a small arboreal marsupial, the Greater Glider (Petauroides volans), fed high-terpene Eucalyptus foliage

The digestion and metabolism of Eucalyptus radiata foliage was studied in a small (1–1.5 kg) arboreal marsupial, the greater glider (Petauroides volans). Mean dry matter intake was 44 g·kg^−0.75·d⁻¹ and mean cell wall digestibility was 34%; these values fall within the range of other marsupials fed Eucalyptus foliage. Digestible energy content of E. radiata was high compared to other eucalypts because of the high content and digestibility of essential oils. However, excretion of essential oils and their metabolites in the urine meant that greater gliders retained only 55% of their digestible energy intakes (0.61 MJ · kg^−0.75· d⁻¹) as metabolizable energy (ME). Low ME intakes were not offset by low standard metabolic rates (2.39 W · kg^−0.75), but the efficiency with which ME substituted for tissue energy was high (94%), so that greater gliders were able to maintain energy balance and body mass on E. radiata foliage.