“A controversial plan to repopulate the grasslands of the western United States with genetically pure bison from Yellowstone National Park got under way in the dark of the night on March 21. Sixty-four of the animals, also known as buffalo, were shipped to Montana’s Fort Peck Reservation, where they will be bred by Native Americans who often regard them with spiritual reverence.
Many of what are called buffalo in the grasslands of the Great Plains are actually hybrids that have been interbred with cattle. Those in Yellowstone are said to be from the world’s last remaining reservoirs of pure bison genetics. They are also free of the disease brucellosis, which can cause pregnant animals to abort their young.
Efforts to ship the bison from Yellowstone have for decades been delayed and blocked by cattle ranchers who feel they will compete with cattle for grazing space. Untold numbers of the iconic animals grazed freely across the American West until they were slaughtered to near extinction during the late 1800s” (source).