The Yahi clan of the Yana Indian nation lived in the Deer Creek and Mill Creek canyons between the Sacramento River and Mt. Lassen in northern California. The Yahi were a small tribe of approximately 300 people. They were hunters and gatherers whose diet consisted of deer, salmon, and acorns. Theirs was a Stone Age society that believed in a sky god and an evil "coyote spirit." They lived in huts made of bark and hide, and were highly protective of their territorial rights - a stance which often caused hostilities with neighboring Indian tribes. Their society was patriarchal; political power was in the hands of the chiefs, who were supported by the community and who had the privilege of keeping pet vultures.

During their occupation of California, the Spanish and Mexicans had little contact with the Yahi. However, when the U.S. obtained California, settlers blazed a trail to the California gold fields through Yahi lands. From the start, this contact involved bloodshed. Transient gold prospectors and cowboys raped and murdered Yahi citizens, and the tribe’s warriors retaliated by killing local settlers and their families. From 1858 to 1870, Americans and Yahi constantly fought. Since the Yahi were sedentary, they were particularly vulnerable to surprise attack. The battles ended when a force of civilian "Indian fighters" attacked and butchered the Yahi in Deer Creek Canyon in 1870. Of 300 Yahi, only 12 escaped the massacre.

The Americans thought they had completely exterminated the Yahi tribe, but the 12 survivors lived on in the wild country around Mt. Lasses in caves and crude huts. The Yahi avoided any contact with the whites, fearing they'd be slaughtered by them, but illness and age reduced their numbers over the years. By 1908 there were only four Yahi left when a surveying party stumbled into their camp. The Indians fled, and three of them died soon after, leaving one Yahi man alive.

He was 50 years old, and after 40 years of hiding from the Americans, this man decided to seek civilization. He wandered out of the mountains to Oroville, CA, where the local police put him in jail on 29 August 1911. When the news of this "wild Indian" who spoke no English or Spanish reached San Francisco, Thomas Waterman of the University of California's Museum of Art and Anthropology came to his rescue. Waterman took the last of the Yahi to San Francisco and housed him at the Museum. It was taboo for a Yahi to speak his own name, so waterman named the man Ishi. An amiable and intelligent individual, Ishi became a permanent resident at the museum, where he helped anthropologists in their studies of his people's language, myths, and culture. He acquired a small English vocabulary, and a few Anthropologists learned some Yahi. Surprisingly, Ishi adjusted to the white man's metropolitan lifestyle and made a few friends. He rode streetcars and attended Wild West shows and vaudeville performances. he claimed that the white man's greatest inventions were matches and glue. Although often treated like a freak, Ishi maintained his dignity and never surrendered his Yahi beliefs, even though he adopted the dress and other trappings of American culture.

On 25 March 1916, Ishi died of tuberculosis at the University of California Medical School in San Francisco.