Energy requirements of weasel high throughout year – survival depends on efficient foraging strategies, selection of appropriate microhabitats and thick winter nests. Made models and tested energy budget by comparing predicted power required to maintain heat body in various circumstances. Inside lemming nest model adults could maintain normal body temp at ambient -20 deg C roughly equal to thermoneutral resting BMR. At -35 deg, (lowest recorded subnivean temp) weasels need 100% more, stoats 50% more energy – then female least weasel confined to nest. Surface temp often -40 or -50, well outside thermoregulation ability of either species, then must stay under snow. Estimated ADMR over a year is 2.9-4 times BMR. Highest ADMR relative to BMR for least weasels (x6) near maximum possible metabolic scope, less for ermine. Enegy requirement may be less during lemming peaks as can spend much less time hunting, more time in nest.Estimated one 40 g female least weasel at Barrow needs 373 lemmings a year, a 130 g stoat 700/year. Lemmings need 160 g forage a year, equates to a large effect on slow growing plants.
|Author||M. A. Chappell|
|Secondary title||Journal of Mammalogy|