Others are hunters and fishermen and are nomadic in habit.
The reason is that interment appears not to have been practised by the river-drift hunters, and the only bones likely to be found would be those accidentally preserved in caves or rock-shelters.
It is this Wale ' circumstance that facilitated the rapid invasion of Siberia Wal er l by the Russian Cossacks and hunters; they followed the omm courses of the twin rivers in their advance towards the east, and discovered short portages which permitted them to transfer their boats from the system of the Ob to that of the Yenisei, and from the latter to that of the Lena, a tributary of which - the Aldan - brought them close to the Sea of Okhotsk.
The north-east extremity of Siberia, and Bering Sea between the land of the Chukchis and Alaska, with the Gulf of Anadyr, are often visited by seal-hunters, and the Commander Islands off Kamchatka are valuable stations for this pursuit.
Soon after the first appearance (1580) of the Cossacks of Yermak in Siberia thousands of hunters, attracted by the furs, immigrated from north Russia, explored the country, traced the first footpaths and erected the first houses in the wilderness.