For the first time the hair microstructure of two individuals of the bison Bison priscus found at the North East of Russia (the basins of Tirekhtyakh River in Yakutia and Rauchua River in Chukotka) have been studied using SEM in comparison with the hair structure of the recent representatives of genus Bison. The high thermo-insulating and hard-wearing characteristics of pelage and of different categories of the hair – guard hairs and wooly hairs – were revealed. The hair microstructure of ancient bison is similar to those of recent bison B. bison and aurochs B. bonasus but its pelage is more differentiated and thick.