Rate of water turnover and electrolyte balance of an arid-zone marsupial, the spectacled hare wallaby (Lagorchestes conspicillatus) on Barrow Island.

The work reported in this paper describes aspects of the water and electrolyte metabolism of free-ranging spectacled hare wallabies (Lagorchestes conspicillatus) on Barrow Island in Western Australia. Two populations were studied in both spring (October) and summer (March). Rates of water turnover were measured in spring with tritiated water and were extreme ly low, approximating 5% of the total body water per day, and these are amongst the lowest rates yet published for any marsupial. Urine outputs were also extremely low and variable in spring, and urine osmolality averaged from 859 to 1015 mOsm/kg. In summer, rates of urine production were significantly higher, but urine osmolality did not change. Osmolar clearance was elevated in animals collected in March, and free-water clearance was more negative but, in view of higher rates of urine production, a significant modification of renal function is not indicated. Previous surveys have indicated that the density of hare wallabies is greater in disturbed areas of Barrow Island. Dietary analysis suggests that this unequal distribution results from a greater availability of preferred plant species growing in these disturbed areas.