Western Whiptail
(Cnemidorphorus tigris)
These particular lizards rank right up near the top as far as speed goes. I think during the entire time I was stationed at Fort Irwin I was only able to catch one or two of them because the second you got with 15 or 20 feet they would bolt 20 yards in the blink of an eye. Most often I would see them sitting under the shade of a creosote bush keeping itself cool from the heat of the sun.