The size of Nenets’ herds varies, depending not only on the owner but also on the seasons. In summer, for example, herds need to be larger to act as a natural defence against mosquitoes. The herds on the Yamal Peninsula will range from 50 in small private herds to 7,000 in the largest 8th Brigade of the Yar-Sale state farm. The migration pattern (see map above) depends on seasons and on sustainability of lichen pastures on which the reindeer feed. The large herds will have their winter pastures in the forest-tundra just to the south of the Arctic Circle, and in spring the brigades begin their migration northwards as fast as possible until the thaw comes. They spend a short summer in the northern tundra close to the Kara Sea and then return southwards to the forest tundra in November. The entire migration covers around 1100 kilometres and includes a 48 km crossing of the frozen waters of the Ob River. For these journeys the reindeer are used to pull sledges that carry the people and their camp. These enormous single-file reindeer trains can stretch out to 8 km in length, as far as the eye can see. A daily migration covers distances between 8-20 km during snow-covered time, and 3-11 km in summer, when the reindeer pull their sledges over the grass. On their winter migration to the south they stop at the administrative centre of Yar-Sale for the annual slaughter, which is where the salaries are paid to the herders and where they are able to make most of their money.