Because the livelihood of the Turkmen depended on their livestock—including sheep, goats, camels, and horses—year-round access to pastures was essential. Every Turkmen tribe had its own pattern of migration and its own preferred winter and summer pastures and springs or oases for watering flocks. This way of life is called pastoral nomadism. It allowed tribal groups that depended on livestock to move where their flocks could graze as the seasons changed. To support this way of life, all their possessions had to be easily portable. Camels were the favored method of transportation because they could traverse rough terrains, carry heavy loads, and subsist on very little water.