Ishi: The Last of His Tribe (1978)

In 1911 in Northern California, a rancher found a naked, unconscious Indian, near death, lying in his horse corral. After he was revived and brought back to health, it was eventually discovered that the Indian, named Ishi, was the last surviving member of a small tribe called the Yahi, which had been decimated by disease, starvation and clashes with other tribes high in the mountains, and was so reclusive that hardly anyone, white or Indian, had ever even heard of them. Ishi was studied and eventually befriended by a San Francisco anthropologist, who wrote a book about him, upon which this film was based.