These little guys, which have been described as a cross between a bunny and a mouse, are undeniably adorable. They are also very picky about where they live. Their physiology requires them to always stay cool, so they can only live at very high altitudes. They can actually die when exposed to temperatures over about 78 degrees Fahrenheit for more than a few hours. They are primarily found in the high Sierra Nevada and Rocky Mountains.
Photo credit to Jon LeVasseur (www.sharetheexperience.org).