One of the greatest fears of the pioneers was attack by Indians. Much of the worry, however, was unfounded. The vast majority of the pioneers never encountered hostile tribes. In fact, during the early years of migration the Native Americans were very helpful to the pioneers traveling west. Indians helped guide many wagon trains through the mountain passes. They were also experts at getting cattle and wagons across rivers. They even supplied the wagon trains with fresh horses, though the price could be quite high. Meriwether Lewis and William Clark would never have made it across the Rocky Mountains without assistance from the Shoshone. Sacagawea, a Shoshone woman, guided Lewis and Clark up the Missouri River as far as their boats would carry them. She also secured horses from her brother, a Shoshone chief, so that Lewis and Clark were able to continue across...