Mavis can't see 'em, but likes being downwind of bison/buffalo. Coincidentally, both of them enjoy eating grass. Guess which one of them gets sick from it.
Camping at the Badlands National Park didn't cost me nuthin' not including my National Parks pass. I didn't have running water and had to get to the campsite via a very-washboarded gravel road, but it was well worth it. We were down from a prairie dog colony where we could hear the squeaks at night, and also had the company of two-to-three bison. They blithely walked through the campground as if nothing was in their way, and you know, they were right!