We have rattle snakes in our parks and on our trails. There are 4 million people here and someone posted on a local website that her dog got bitten by a baby rattler (the dog was big) and there were exactly four places with anti-venom. So please if you’re in the Southwest particularly the desert you don’t let your dog wander. The dog survived because it was a baby snake (they tend to strike more often than mature snakes) and the dog was big. But it’s serious.