Rattlesnake range is extensive— from southern Canada to central Argentina. The thickest concentration is in the US Southwest and northern Mexico, according to the National Wildlife Federation. The estimated 36 rattlesnake species are adaptable, living in forests, grasslands, swamps and deserts Rattlesnakes are "pit vipers" with heat-detecting pits on their heads. Other US snakes in that family are copperheads and cottonmouths, also called water moccasins. These latter two species are concentrated in the central and eastern United States, whereas multiple species of rattlesnakes range across the United States. Fully grown rattlesnakes are typically between 36 and 46 inches long. Most pit vipers typically deliver a "hemotoxic" venom that attacks the circulation system, destroying blood vessels and causing tissue damage. The only other venomous snakes in the United States are coral snakes. Known for their bright bands of red, yellow and black, they are in a different snake family that's related to cobras. They deliver a neurotoxin that disrupts nerve transmission and can cause respiratory failure and paralysis.

Where do snakes hide?
Rattlesnakes constantly hunt for shelter. They hide under logs and in stump holes. They also like woodpiles, thick brush and spaces under boulders, experts say.  Pit vipers some times take up residence where people live and work— especially if hiding spots and their food supply (mostly small rodents and lizards) are plentiful.  However, rodents are much more likely to get into your house than snakes. If snakes do get into your house, it's most likely you have a rodent infestation. In this respect, rattlesnakes play a key role in balancing the environment. They're mostly eating mice and rats— they're out there doing free pest control.

Do people die from snake bite?
Deaths in the USA from venomous snakes are rare. The US Centers for Disease Control and Prevention estimates about 7,000 to 8,000 people are bitten by venomous snakes in the United States each year. About five of those people die. While human death from a rattlesnake bite is rare, bites will cause a great deal of pain and almost always require a hospital visit to prevent further complications. "The number of deaths would be much higher if people did not seek medical care," the CDC says. World estimates for death by venomous snakebite are much higher -- 81,000 to 138,000 each year.

Rattlesnakes are also afraid of us
Rattlesnakes' reclusive nature is one reason why there aren't more incidents. The rattlesnake actually views humans as a predator; we're a large animal that could eat him. And they're afraid of us, say experts. Rattlesnakes tend to stay hidden. When we encounter a snake on the move, he's usually looking for food or looking for a mate or looking for shelter. Otherwise, he stays hidden because they're so vulnerable to all sorts of predators. Rattlesnakes are "sit-and-wait predators. Some will sit in one place for over a week waiting on a meal. So when there's an encounter, people have generally encroached on their territory.

What to do if a rattlesnake bites you
If you are bitten,  seek medical attention as quickly as possible say the experts. If you can, call 911 to come get you. You'll know if you have a serious bite in just a couple of minutes; you can start to feel tingling in your face. According to the California Poison Control System, other symptoms could include:

•  Extreme pain and swelling at the bite
• Lots of bleeding
• Nausea, lightheadedness and drooling
• Swelling in the mouth and throat

But what if you can't make that SOS call?

• Keep your heartbeat as low as possible. It takes a while for the venom to work. Don't run, but get yourself somewhere you can make a phone call immediately. There's nothing to really help you from the venom except the serum.
• Stay as calm as possible and deep breathe. Don’t let yourself fall asleep.
• If possible, use a marker or pen and circle where you were bitten in case of swelling. Medical personnel will need to know the bite point.
• Remove jewelry such as rings and tight clothing before you start to swell.

What NOT to do if a rattlesnake bites you

• The best emergency response to a snakebite is car keys and a cell phone!
• Don't employ the out-of-date advice of cut-and-suck (cutting an X at the bite area and sucking the venom out by mouth or suction cups). It's very ineffective; people are likely to do more damage from the knife cut than from the snake bite.
• Do not elevate the affected area! Keep the bite below the level of the heart.
• Don't try to kill the snake to bring to the hospital, and don't take a picture of it unless you can do so easily. Don't comprise your safety by forcing another interaction with an already defensive rattlesnake. Your response to a bite should be the same no matter which type of pit viper bites you.
• Don't apply ice or cold packs to the bite .
• Don't use Advil, Motrin or other nonsteroidal, anti-inflammatory drugs.
• Don’t apply a tourniquet to a pit viper bite. That venom is concentrated and it works like an acid. It breaks down blood vessels and multiple skin tissues. If you confine that venom in that area, you're apt to lose a limb from that. If you allow it to spread, you're more apt to keep your hand or fingers.

How to avoid a snake bite
Rattlesnakes are most active in spring and fall, but vigilance is important all year. Snakes really can venture out in winter on a sunny day.  Always be careful where you put your hands and your feet, especially when working around woodpiles or clearing brush. Wear thick gloves. If you're reaching under your house, shine a light under there first to make sure the coast is clear.

• Wear closed-toe shoes or snake proof boots that fangs cannot penetrate. Snake gaiters help protect your lower legs. Snake chaps offer more coverage than just your lower legs.
• Make plenty of noise and vibration while walking. Stick to well-used trails.
• Go around a rattlesnake on a wilderness trail if you spot one.
• If you find a rattlesnake in your yard, call agencies such as your state's natural resources departments or US Fish & Wildlife or contact a biologist at a local college. Do not try to kill the rattlesnake because that's when most people get bit.
• If you must deal with a rattlesnake on your own,  use a long branch or pole to gently nudge the snake toward an escape route if you're at least six feet or more away.
• What do you do if you hear that bone-chilling rattle? Experts say if he's rattling, he's alarmed. If you can tell where the snake is, back away. Don't approach. Rattling does not necessarily occur  before every bite.