Comparative field energetics of two macropod marsupials and a ruminant

Field metabolic rates (FMRs) and water influx rates were measured via the doubly labelled water method in wild Tasmanian pademelons and grey kangaroos living in the Jock Marshall Reserve at Clayton, Victoria, and in wild black-tailed deer free-ranging within a nature reserve at Davis, California. Deer expended more than three times more energy per day than similar sized grey kangaroos. Feeding rates required to achieve energy balance were estimated from FMRs along with an estimate of metabolisable energy content of the food. The estimated feeding rates for pademelons and kangaroos were combined with similar values for five other species of macropods to calculate an allometric (scaling) relationship for food requirements of macropod marsupials. Feeding rate has the following relationship to body mass: G food (dry matter) consumed per day = 0-20 g body mass⁰’⁷⁹ (r² = 0-94). The findings reported herein should be useful for predicting the approximate food requirements of free-ranging macropods and deer for purposes of ecological modelling, conservation efforts, and management programs.