Ken Burns has created a documentary, “The American Buffalo.” It will air on PBS on October 16. The history of the indigenous people of America is intimately connected to the buffalo, who, in the words of Burns, “fed their bodies and nourished their spirits.” The buffalo was “the grocery store and the church.” As industries in the nineteenth century discovered how to use their hides for belts to run machines, the result was the largest slaughter of an animal in the history of the world. Recent protections have brought the buffalo back from the brink of extinction. This extensive documentary, about 250 hours, promises to fill a chapter of unmistakable significance in the history of North American Indians. Finally, it raises the question, now what?