I once had a class on the proper procedure for dealing with desert tortoises. According to federal law, one may not harass, engage, touch, prod, move or otherwise molest tortoise, this includes yelling and insults. As mentioned in another post, a peculiar defense mechanism of the tortoise is that it will "drop its bladder" in an effort to scare off the perceived predator. And because tortoises by and large only get liquids through eating (not drinking), this will almost certainly lead to death by dehydration. One cannot just put a bowl of water in front of the tortoise and expect it to rehydrate (not the most "fit" animal in the Darwinian sense, save its 120-year life span). As for the proper thing to do if one believes a tortoise is in danger from off-roaders who may happen along, my advice--if one wants to stay withing the law and also not risk a bladder drop--is to wait near the tortoise and flag down any potential threats before they can injure the animal. Do this until the tortoise moves away from the exposed area on its own accord. I know this is asking alot, both in terms of the time it might mean waiting around and also the potential risk of getting hit by some "pedal-to-the-medal" off-roader. Like I said, though, this really is the only way to comply with federal law and still help the animal. The law is so strict, for example, that if a desert tortoise were to crawl under your parked 4-wheeler, you cannot move the vehicle until the tortoise decides to leave--not even if there is absolutely no risk of running it over. And as we all know, tortoises don't hurry. I would recommend that one not touch the animal; the illegality notwithstanding, I know I wouldn't want to be the one to cause it to drop its bladder and die when I am only trying to save it. That said, a friend had a dessert tortoise that I handled on occassion without incident, but that is a different scenario (if needed, the tortoise could rehydrate by eating tons of lettuce, not an option in the desert). Use your judgement; if we are talking about an off-road race with multiple vehicles barreling down upon the tortoise and death is imminent and likely, the lesser evil may be to violate the law. But you didn't hear that from me...