The Sonoran Desert is known for its diversity of rattlesnakes. Rattlesnakes are extremely well adapted to their rodent hunting lifestyle. They're equipped with heat vision for night hunting during the hottest times of summer, a unique scent organ they use in association with their forked tongue, folding hypodermic fangs, and one of the most complex venoms in the world to immobilize their small prey.
The majority of people bitten by rattlesnakes are bitten while handling the snakes. If you see a rattlesnake while hiking, keep your distance, they can bite up to 2/3's the length of their body. Be patient and the snake will move. If you are bitten remain calm, less than 1% of all people bitten in the United States (by any venomous snakes) die. Half of all rattlesnake bites are dry, no venom is injected. Do proceed to the nearest hospitable to receive antivenom, just in case. Even in "fatal" bites there is usually a two hour time period to get to a hospital .