Archaeologists, including Alfred Kroeber, have speculated that the Yuki have been resident in California for many thousands of years and once occupying a greater area than their historic homeland in Mendocino County.

They are described as short in stature and long-headed (Dolichocephalic), unusual in American Indians, but perhaps similar to the extinct Guaycura and Pericú of Baja California, also believed by archaeologists to be ancient residents of the Americas.

These events and tensions led to the Mendocino War (1859), where militias of white settlers killed hundreds of Yuki and took others by force to Nome Cult Farm.

Between 1854 and 1864, settlement policies, murders, abductions, massacres, rape-induced venereal diseases, and willful neglect at Round Valley Reservation reduced them from perhaps 20,000 to several hundred.

[10] His research thus challenges the idea that the indirect effects of European colonization were the leading cause of population decline and mass death for Native Americans.

[17] Intermarriage among neighboring tribes after their forced relocation to the Round Valley Reservation resulted in large numbers of Native Americans with mixed ancestry.