Yellowstone National Park, Wyoming. The Hadyen Valley.
You can get pretty darn close to the bison herds here; but avoid getting TOO close for your own safety. This was taken with a 100-400 mm lens.
This curious juvenile bison wanted to get a good sniff of the weeds he was about to it chomp. Perhaps he was exercising a lesson he had learned from his parents about sniff before you eat. The look on his face clearly communicated a look many youngsters, two- or four-legged, have when they relate to something interesting or intriguing in the world around them.