Sixty-three-year-old Dan Fox and Man Blackpume of the Kainai First Nation Native American tribe raise 30 bison. It's a blustery cold October afternoon in southern Canada. They are part of a larger movement to bring bison back in North America. The bison, an integral part of the biodiversity, resiliency and vitality of North American ecosystems, were killed off in great numbers over 400 years from the early 1500s, when their population is believed to have been 30-60 million to just 1,000 in the early 1900s. Fox and Blackpume, along with other indigenous people and scientists are working to bring the bison back. Their efforts join others working on bringing back North America's the bison population. They now number more than 500,000.