We did get to see bison on this trip. Here's a close-up. Please note: This bison was close to the road and I stayed in my car. I also used my telephoto lens. I don't want anyone to think I was stupid enough to get out of my car and approach one of these huge unpredictable animals.
I also managed to get a picture of one of the prairie dogs and some of the donkeys hanging out in Custer State Park. Custer State Park and Wind Cave National Park are right next to each other. We had to go through one to get to the other.