Population structure, fecundity and participation in females’ reproduction of different age, feeding trends and fatness of sable have been studied under the conditions of the cold climate in the western offsets of the Verkoyansk Mountains. Comparatively simple age structure and fast change of the generation in the population, increased mortality of matured females and many junior age groups in the maternal livestock population, increase of the mean size of the brood have been established. Sables of low fatness made up over 2/3 of the population. Change in their fatness depended on the level of animal food consumed. In some years nutritional importance of the mountain pine seeds increased. The least fatness was peculiar to females of the reproductive age and we consider it as one of the causes of their increased winter mortality