The forest-tundra zone, 1970.
The climate of the Far North of Siberia is sharply continental with short, hot summers and long, cold winters. Natural environmental and climatic conditions control the distribution of both plants and animals in this region. The reindeer is a unique animal of the Far North. The structure of the reindeer's wooly winter coat, which has soft underwool and rough guard hairs (fusiform with large hollow horny cells inside), provides for good thermal insulation, an adaptation to the rigorous climate. The presence of wool, not only on the body but also on the snout, permits the reindeer to collect food from the frozen ground in the winter without injury to the mucous membranes of the lips and the nose. Movability of the hoof permits procurement of yagel moss during winter from beneath deep snow and thin ice. The reindeer anatomy is ideal for locomotion in the tundra. Reindeer feed throughout the year on pasturage, on yagel moss in winter, and on the greenery of young plants in spring and summer. The instinct in wild reindeer to migrate is associated with the characteristics of feeding and the abundance of blood-sucking insects in summer. Reindeer are subdivided into those inhabiting mountains, tundra, and forest. Mountain reindeer spend most of the year in the Alpine zone above the timberline, constantly migrating to the mountain tops in the summer, and moving in the winter towards the timberline, where there are bushes and small trees. Tundra reindeer migrate during the summer throughout vast expanses of the Arctic tundra and return to the timberline during the winter. Forest reindeer live within the forest zone. Their major migration route passes between river valleys and along swamps, alpine plateaus, and ridges.