We were driving through Doris Campground - part of the Wichita Mountains National Wildlife Refuge outside Lawton, OK - and one of the 'rocks' barely visible in the deep shade stood up.
The fully mature male buffalo nudge the mirror on my truck, which thankfully folded in as designed. My wife hastily rolled up the window. He just stared at us from a couple inches away as I slowly pulled away.
While driving from the steak house to the El Tovar Hotel one night at the Grand Canyon, a bull elk butted the rental car window. I had stopped when I saw him close, but he came over and tried to get us to ??? - my guess is people in cars had fed him at some time in the past.
Last summer while we were campground hosts at Big Bend National Park Chisos Basin Campground, twice young Mexican Black Bear walked out of the underbrush less than 10 feet from me.
The only time I was really worried was a young boy - 7-9 years old - from France walked up to a young buck deer with velvet covered antlers about 14 inches long and tried to feed it grass he had picked. We cautiously got him away from the deer.
I'm not going to mention the few rattlesnakes we saw. Those are the ones which I am most careful about.
