Hopi Legal Action

Arizona's Hopi Indians are hopping mad that French auction house Neret-Minet is due to sell a collection of 70 of their sacred masks and headdresses tomorrow. London-based charity Survival International, which is the only organisation in the world that campaigns for the rights of tribal peoples, has secured a court hearing in Paris in an attempt to stop the sale going ahead (CLICK). This news is briefly mentioned on Survival's website (CLICK). Shown is the Wakaskatsina Sacred Mask. What puzzles me is: When did the European cow become a sacred object for Hopi Indians?