Reproductive plasticity of the American mink Mustela vison in Belarus

Abstract

Mating period of American mink lasted from mid February to mid April. Young were born from April til mid June. Litter size was on average 4.2 (blind cubs) and 3.3 in older cubs (>2 months old). Reproduction intensity on Drissa river and its tributaries was related to density. On average, 3.3 embryos per pregnant female were found in 1-yr females and 4.3 in ≥2-yr old females at the density of 13.3 mink/10 km of watercourse. In the low density population (2.8 mink/10 km due to overexploitation by hunters) reproduction intensity increased to an average of 4.2 embryos in 1-yr females and 6.0 in ≥ 2-yr females. During population decrease, percentage of young increased and the sex ratio became biased towards females. In an expanding population of mink that had newly colonised Lovat river, reproduction was very intense (7.3-7.6 embryos/female). The great reproductive plasticity helped this species to successfully colonise new ranges after introduction. -from Author