X is for Fox (Only if it is spelled backwards)
I know. Fox starts with 'F'. I just couldn't find a Yellowstone animal whose name started with 'X' so I had to cheat. Sorry about that!
Did You Know?
Yellowstone contains approximately one-half of the world’s hydrothermal features. There are over 10,000 hydrothermal features, including over 300 geysers, in the park.