Coprophagy and Selective Retention of Fluid Digesta: Their Role in the Nutrition of the Common Ringtail Possum, Pseudocheirus Peregrinus.

Abstract

In ringtail possums, Pseudocheirus peregrinus, fed a sole diet of Eucalyptus andrewsii foliage the mean retention time of the fluid marker 51Cr-EDTA in the gut (63 ± 2 h) was longer (P< 0.002) than that of the particulate marker 103Ru-phenanthroline (35 ± 2 h), indicating selective retention of fluid digesta in the caecum. In addition, the ringtail was observed to be coprophagic. The form of coprophagy was determined to be caecotrophy; hard faeces produced during the dark (foraging) phase were not eaten, but soft faeces produced during the light (resting) phase were taken directly from the cloaca. Soft faeces, collected when coprophagy was prevented by a plastic collar, were high in water and nitrogen content, and low in fibre relative to hard faeces. Coprophagy contributed 254 kJ.kg-0.75.d-¹ to total energy intake (equivalent to 58% of digestible energy intake), and 570 mg nitrogen per kg-0.75per day, twice the main- tenance nitrogen requirement. It was concluded that coprophagy was an important factor in explaining the ringtail possum's low requirement for nitrogen and its ability to subsist on a sole diet of Eucalyptus foliage.