One advantage of curious friends is that we are always asking questions...did you know that this is not a 'Buffalo'? We discovered, through extensive research (cell phone Google :), that this is a 'Bison'. Often called the 'American Buffalo', but not a buffalo at all.
This fellow was enjoying some (very) early morning slumber when a group of ernest photographers accidently found him along the trail. All was okay until he abruptly stood up...we kept our distance. Bison can be dangerous and should never be approached. They attack more people in Yellowstone each year than any other animal. A bull bison can stand six feet tall, weigh up to 2,000 pounds, and run at speeds up to 30 miles an hour.