During this period there is continuous sunshine, but the soil thaws only to a depth of 2 or 3 feet. As temperatures rise towards the end of May, snow and ice melt on every land.
In the flat Kolyma basin, since the frozen sub-soil is impervious, the low-lying country becomes a vast stretch of lake-studded marsh traversed by innumerable stream channels and land travels become almost impossible.
The hardy trees, stone pine, larch, birch and alder clothe the mountain slopes. The northern plains support only a scanty vegetation of sedge grasses, mosses, lichens and low berry bearing bushes.
These burst suddenly into life when short summer begins and support the animals, which then move out over the tundra. The polar hare, elk and reindeer and great flocks of geese, duck and ptarmigans appear miraculously to be preyed upon by man.
In the forest to the south the black bear, musk deer, squirrel and mountain sheep are found. Although salmon are rare, a large number of other fish ascend the rivers in spring for long distances, returning to the sea in late summer before the rivers freeze again.
The herds of wild reindeer are by far the most important source of food and skins for Yukaghirs. The wild reindeer are but little smaller than the east Siberian horse.
They migrate seasonally on either side of the forest border. In winter most of the herds seek the shelter of the wooded country, where they find carpets of lichens in openings of the forest, though one variety remains on the tundra throughout the year.
Reindeer eat twigs, fungi and shrubs, but reindeer moss and lichens are the favorite. With their sharp hooves and strong forelegs they can scrape away the snow to surprising depths to uncover the vegetation, while in summer, splaying out their movable toes, they can move easily over marshy ground that could not support other animals of their size.
When the rich carpet of mosses and lichens springs up after the thaw on the tundra, the woodland reindeer migrate northward, where they can find some relief from the great swarm of mosquitoes which torment all animals in summer on the forest border.
Yukaghirs are Mongoloid by race. They are short thickset people with flat but narrow faces, small snub noses, yellow-brown skin colour and coarse straight black hair. Their clothes are of reindeer and other furs.
A sack-like coat of reindeer hide reaching to the knees, with long sleeves hide coats with the fur left on are worn one above the other. A long front apron of hide also hangs 4own from the neck.
Leggings and long boots are worn by both sexes. They migrate and camp in small groups of families which rarely exceed one hundred persons in all and are often smaller. Individuals rarely marry outside their group.
The main mode of migration and transportation is sledge. The dog sledges are generally two metres in length which are made of Birchwood. The sledge can also be used on smooth mossy ground after the snow has melted. For transport on the main rivers larger rafts are made by tying large poles together.
The winter camps are moved two or three times between October and May to hunt the game of fresh tracts of forest. With sinew-backed bows and firearms, they hunt the reindeer that have also retreated south, and make expeditions into the forested uplands for elk, musk deer and mountain sheep.
The best hunting periods are in autumn and spring. The surplus from the spring hunting and fishing must be dried if it is to be preserved, but the stores accumulated during summer provide food and nutrition during winter. Barriers, lily bulbs, the inner bark of larch, and the juice of red poplar and other wild wood plants are gathered in the summer season.
The produce of hunting and fishing are not kept by individuals but are handed over to the ‘old man’ whose wife distributes it. Tents, nets and boats are the property of the group or more occasionally the family, and personal property is practically restricted to the thing and individual hunting weapons.
Throughout the year they live in conical tents of light poles covered with reindeer skins, which they pack on the dog sledge and rafts when moving from place to place. In the winters they live in small villages of pit-dwellings excavated a few metres deep and covered with timber and sods.
The young men are rigorously trained for the difficult and exhausting task of reindeer hunting for a herd once disturbed moves off with great speed and must be followed relentlessly for days if a kill is to be made. The leading hunter of the group, like the ‘strong man’ who organized the defence of the group or its territory, attains and keeps his position only by display of great bravery, strength and resourcefulness.
In recent decades, there had been rapid transformation in the Yukaghir society. Many of them have joined adjacent reindeer herding groups, particularly the Tungus. They are, however, the representatives of the most primitive economy in north-eastern Asia.
Among them are found the only examples of exclusively food gathering communities in Arctic Asia. In their diet, the reindeer meat and river fish are the most prominent elements and their food habits are not likely to change in near future.
The Russian government is trying to change their economy from the hunting and gathering to the reindeer herding but the extreme cold conditions are coming in the process of planning and development.
Transformation of habits is difficult in any set of environment, especially in the deterministic climate conditions of north-east Siberia.