Ecological aspects of winter dormancy in the striped skunk (Mephitis mephitis)

Abstract

Seasonal surface activity patterns of captive and free-ranging skunks at Delta Marsh, Manitoba, Canada, were determined using radio telemetry and visual observations. Activity decreased sharply between Sept. and mid-Dec., and was virtually nil between Dec. and early April. Surface activity resumed in March and increased sharply in April to summer levels. Body temperature (Tb) was studied in 2 individuals in July and 3 individuals in other months using abdominally implanted radio transmitters. Mean Tb, maximum diel range and minimum Tb were 37.7, 2.2 and 36.2.degree. C respectively in July, and 34.4, 7.2 and 28.4.degree. C in Jan. Body fat content of adult males, determined by ether extraction, was 32% of live weight in Oct., and 10% in late April and early May. Theoretically, the skunks experience an energy deficit of 44% if they exist at basal metabolic levels for a winter period of 140 days. The winter reduction in surface activity, the retreat to a relatively warm den, and the winter depression in body temperature permit the striped skunk in the northern portion of its range to survive the winter relying exclusively on stored fat as an energy source, without resort to true physiological hibernation.