Metabolic, hygric and ventilatory physiology of a hypermetabolic marsupial, the honey possum (Tarsipes rostratus).
The honey possum is the only non-volant mammal to feed exclusively on a diet of nectar and pollen. Like other mammalian and avian nectarivores, previous studies indicated that the honey possum's basal metabolic rate was higher than predicted for a marsupial of equivalent body mass. However, these early measurements have been questioned. We re-examined the basal metabolic rate (2.52 +/- 0.222 ml O(2) g(-1) h(-1)) of the honey possum and confirm that it is indeed higher (162%) than predicted for other marsupials both before and after accounting for phylogenetic history. This, together with its small body mass (5.4 +/- 0.14 g; 1.3% of that predicted by phylogeny) may be attributed to its nectarivorous diet and mesic distribution. Its high-basal metabolic rate is associated with a high-standard body temperature (36.6 +/- 0.48 degrees C) and oxygen extraction (19.4%), but interestingly the honey possum has a high point of relative water economy (17.0 degrees C) and its standard evaporative water loss (4.33 +/- 0.394 mg H(2)O g(-1) h(-1)) is not elevated above that of other marsupials, despite its mesic habitat and high dietary water intake.
Department of Environmental and Aquatic Sciences, Curtin University of Technology, Centre for Ecosystem Diversity and Dynamics, Bentley, WA, Australia. C.Cooper@curtin.edu.au
Christine Elizabeth
CE
Cooper
Ariovaldo P
AP
Cruz-Neto
D000704:Analysis of Variance; D000818:Animals; D000835:Animals, Wild; D001481:Basal Metabolism / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology*; D001834:Body Water / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D002245:Carbon Dioxide / Q000378:metabolism; D003080:Cold Temperature; D005260:Female; D016018:Least-Squares Analysis; D008176:Lung Volume Measurements; D008297:Male; D008394:Marsupialia / Q000378:metabolism / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D010802:Phylogeny; D010993:Plethysmography, Whole Body; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012119:Respiration; D012621:Seasons; D014870:Water Loss, Insensible / Q000502:physiology; D014904:Western Australia
D002245:Carbon Dioxide