Top%3A Black bears%2C deliberately fed and habituated to human food%2C provide entertainment for park visitors at West Thumb Camp in 1924. Photo just above%3A Bison in the %22Mammoth Showpen%22 in 1924 when wildlife%2C in order to insure visitors saw animals%2C were really managed as if in a glorified zoo. Photographer unknown%252Fcourtesy NPS