I recently participated in a Tortoise Habitat plant survey/trash cleanup event out in the desert. Before we wandered off to photograph plants and look for signs of tortoise activity the organizers talked about snake awareness/safety; right in the middle of that we saw the tortoise biologist walking towards us from the parking area, carrying a covered bucket. He'd heard what sounded like air leaking out of a tire, looked under his truck and found a beautiful Mojave Green rattlesnake. :) The snake was extremely active - he could only carefully raise the lid for a few seconds at a time before snakey tried to fly out - and his rattle was going... (once everyone got a good look at the snake he released it a safe-ish distance away)