The East Siberian brown bear (Ursus arctos collaris) is a population or subspecies of brown bear which ranges from eastern Siberia, beginning at the Yenisei river, north to the Arctic Circle, as far as Trans-Baikaliya, the Stanovoy Range, the Lena River, Kolyma and generally throughout Yakutia and the Altai Mountains. The subspecies is also present in northern Mongolia, northern Xinjiang, and eastern Kazakhstan.
East Siberian bears are intermediate in size to Eurasian brown bears and Kamchatka brown bears, though large individuals can attain the size of the latter. Their skulls are invariably larger than those of Eurasian brown bears and are apparently larger than those of Kamchatka brown bears.
Adult males have skulls measuring 32.6–43.1 cm (12.8–17.0 in) in length, and 31.2–38.5 cm (12.3–15.2 in) wide at the zygomatic arches. They have long, dense and soft fur which is similar in colour to that of Eurasian brown bears, though darker coloured individuals predominate.
Given the vast, wild, and virtually uninhabited territory which they inhabit, Siberian brown bears tend to be much less skittish with the presence of humans, as opposed to the Eurasian or some American brown bear subspecies. European brown bears, for example, as they inhabit a continental area far smaller than Siberia or Russia, are generally warier of people, as they are, more or less, persecuted and feared throughout their range. Both literally and figuratively, European bears are "surrounded" by humans and their dogs on all sides, on an already-cramped continent, a harsh reality which dictates their very movements and behaviours. Thus Siberian brown bears have no fear, and will readily destroy any vulnerable or unprotected food source, including hunters' outdoor food stores, and even homes or huts where there is any enticing scent, leading to potential human-bear confrontations.
