Why did chief Joseph lead the Nez perce on a 1500 mile retreat westward?

Chief Joseph led the Nez Perce on a 1,500-mile retreat westward in response to increasing pressures from U.S. government policies that sought to forcibly remove his people from their ancestral lands in the Pacific Northwest. In 1877, after the U.S. government attempted to relocate them to a smaller reservation, Chief Joseph sought to evade capture and protect his tribe's way of life. His retreat aimed to reach Canada, where they hoped to find refuge and safety from American military forces. Ultimately, the journey showcased the resilience and determination of the Nez Perce, despite their eventual surrender.