According to the National Park Sevice, "In North America, both 'bison' and 'buffalo' refer to the American bison (Bison bison). Generally, 'buffalo' is used informally; 'bison' is preferred for more formal or scientific purposes. Historians believe that the term 'buffalo' grew from the French word for beef, 'boeuf.' Some people insist that the term 'buffalo' is incorrect because the 'true' buffalo exist on other continents and are only distant relatives."
"Another name for these animals is 'tatanka.' Tatanka is the Lakota word for bison. Bison are incredibly important in Lakota culture; the Lakota are traditionally nomadic and would have spent their lives following bison before Euro-Americans settled the West. Another word for bison in Lakota is 'pte.' The Lakota are sometimes known as pte oyate, meaning 'buffalo nation'."
Visit Wind Cave National Park and you'll see bison grazing the rolling hills, resting in the grass, or standing on the road. Keep a safe distance from these behemoths. Use your telephoto lens. And, please don't pet the "fluffy cows."