Wintu tribes, and markedly dissimilar to those of Yahi, Shackley suggested that Ishi had been of mixed ancestry, and related to and raised among members of another of the tribes. He based his conclusion on a study of the points made by Ishi, compared to others held by the museum from the Yahi, Nomlaki and Wintu cultures.

Among Ishi's techniques was the use of what is known as an Ishi stick, used to run long pressure flakes. This is known to be a traditional technique of the Nomlaki and Wintu tribes. Shackley suggests that Ishi learned