Fur trade marten furs could generate in international markets spurred a "fur fever" in which many Russians moved to Siberia as independent trappers. From 1585 to 1680, tens of thousands of sable and other valuable pelts were obtained in Siberia each year. The primary way for the Muscovite state to obtain furs was by exacting a fur tribute from the Siberian natives, called a "yasak". "Yasak" was usually a fixed number of sable pelts which every male tribe member who was at least fifteen years old had to supply to Russian officials. Officials enforced "yasak" through coercion and by taking hostages, usually
Northern goshawk at is the smallest marten and is sometimes taken as prey by the goshawks, successfully ambushed and preyed on a brooding female goshawk. In Chequamegon-Nicolet National Forest of Wisconsin, the main source of mortality for northern goshawks is reintroduced fishers ("Martes pennanti"), which are the largest kind of marten at and capably kill many chicks, fledglings and brooding females. In contrast, in Europe, the pine marten ("Martes martes") has only been known to prey on young goshawks still in the nest and not adults. Other mammals capable of climbing trees have been observed or inferred to predate goshawks, either mostly