The Nez Perce Indians lived in scattered villages in the Plains west of the Rocky Mountains. About 4,000 in number, they were excellent horsemen and owned the largest horse herd on the continent. They fished for salmon along the Clearwater and Snake rivers, and harvested camas plants in mountain meadows.
Like their Shoshone neighbors, the Nez Perce were without guns or ammunition. This left them vulnerable to their enemies, who could obtain weapons from Canadian traders, and it threatened their ability to hunt buffalo. The Nez Perce had heard about the expedition and had looked for the Corps to bring them the guns they needed.
Every year, Nez Perce hunters would cross over the difficult Bitterroot Mountains and hunt buffalo. By late September 1805, the Corps of Discovery had completed the same grueling passage by following the Lolo Trail used by the Nez Perce.
That month, three young Nez Perce boys spotted Captain William Clark and a few men approaching the cluster of Nez Perce lodges. Clark and the men had pushed ahead of the Corps to seek out the Nez Perce. The boys were frightened and hid in the tall prairie grass, but Clark found them and offered each a ribbon, signaling that friendly visitors had arrived.
Many of the Nez Perce men were away on a raid and would not return for two weeks. But the Nez Perce were not frightened of the white men and treated them to a filling meal of buffalo, dried salmon, and camas bread.
The Indians told Clark about the route ahead. Among those offering guidance was Twisted Hair, a chief that Clark described as "a Cheerful man with apparant siencerity."
Twisted Hair and other chiefs met for council with Clark and with Meriwether Lewis, who had by then arrived with the rest of the Corps. Communication, even signaling, was difficult because the Nez Perce spoke a notably different dialect than many of the Indians to the east. The council was reduced to an exchange of gifts, but both groups seemed satisfied.
The Corps remained among the Nez Perce for several days preparing for the rest of their journey. Twisted Hair and two of his sons helped Clark find good timber for making canoes, and the captains traded goods for horses, which they temporarily left in the Indians care.
On the Corps' return journey in May 1806, they returned to the lodges of the Nez Perce to reclaim their horses and prepare to cross the mountains. While there, Lewis and Clark engaged in a diplomatic exchange with Nez Perce chiefs. The captains sought to establish trading posts and intertribal peace in the region. The Nez Perce were willing to cooperate as long as the Corps provided guns and other weaponry to the Nez Perce.
The Nez Perce camps granted timely refuge for the expedition. The Corps stayed near the Indians from May to June, waiting for the snow to melt and render the mountain passable. The Indians and the Corps members interacted often. In exchange for a continual food supply, Clark frequently treated the Indians' illnesses and diseases and became, as Lewis wrote, their "favorite phisician."