Why were Great Basin bands usually small and frequently moving?

Indigenous peoples of the Great Basin lived in small, mobile bands primarily due to the challenges of their arid environment and the nature of their food resources.1

Because the region is largely desert, food supplies were often scarce and scattered, making it difficult for large groups to remain together for more than a few days. To survive, these groups followed an "annual round," moving frequently through different ecological zones to exploit plant and animal resources as they became seasonally available. By relocating their summer encampments, they ensured that they did not exhaust the food resources in any single locale.123

These bands typically consisted of extended families with fluid membership, coming together in larger groups only during specific times of abundance, such as spring rabbit drives, autumn piñon nut harvests, or fish spawning runs. While the adoption of horses later allowed some groups to remain in larger numbers for longer periods, the fundamental necessity of tracking seasonal food sources remained a defining characteristic of their traditional lifestyle.13