Levels of Wounding in the Meadow Vole, Microtus pennsylvanicus

Abstract

Changes in aggression based on levels of wounding were determined from a peak and declining population of meadow voles, Microtus pennsylvanicus, from Virginia. Monthly samples yielded more than 600 live-trapped voles for which reproductive estimates and wounding counts were made over a 23-month period. Puncture wounds and pigmented scars, detected on everted skins of autopsied voles, were graded by a wounding index and analyzed by Chi-square tests. Levels of wounding were comparatively great in males, in winter-caught voles of both sexes, among males from reproductively active months, and among fertile males but not females. More than half of the females were wounded. Wounding was not positively related to population density in males or in females, and may in fact have been most severe in low density, declining populations.