How Bear Spray Works

By: Charles W. Bryant
Werner Herzog
Mammal Pictures Director Werner Herzog conducts interviews before the screening of "Grizzly Man" at the American Museum of Natural History's LeFrak Theater. See more mammal pictures.
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In the late 1980s, a young man from California went into the bears -- his name was Timothy Treadwell. He'd recently recovered from a drug overdose and went to view the bears on a recommendation from a friend. Treadwell went on to spend 13 summer seasons observing the bears and came to be known as the "Grizzly Man." He achieved a fair amount of notoriety through his self-penned book and multiple TV talk show appearances. Discovery Channel aired an eight-episode series in August 2008 called "The Grizzly Man Diaries" that showed how Treadwell documented much of his time among the bears with a video camera. That show and filmmaker Werner Herzog's 2005 documentary, "Grizzly Man," offer a fascinating up-close look at the dedicated, if somewhat misguided, naturalist.

What makes Treadwell's story so riveting is not that he lived with grizzly bears -- it's what happened to him at the end of his 13th season. On October 5, 2003, Treadwell and his girlfriend Amie Huguenard were attacked, killed and partially devoured by one of the bears he lived with and loved. Even more startling, the audio of the attack and Treadwell's final six minutes of life were captured on tape by his video camera.


Many felt that Treadwell helped to raise awareness for the preservation of these animals. Others felt that he was a danger to the bears and anyone else who followed in his footsteps. No matter what, there's little doubt that if Treadwell had been armed with bear spray, he would have had a much better chance at surviving a bear encounter. Treadwell carried the pepper spray for protection on many of his trips, but ceased to bring it along beginning several summers before he was killed.

In the entire 20th century, 44 people were killed during bear attacks in the United States and Canada. Twenty-nine of these attacks came in the 1990s, and 11 fatal attacks occurred between 2000 and 2005 [source:]. This shows that the number of attacks is on the rise, most likely because people and bears are sharing space like never before. We have a desire to be one with nature, there's no doubt. Because of this, we should respect the dangerous predators in the woods where we camp, hike, hunt and fish, and take precautions to avoid harm to ourselves and the animals. Bear spray is safe, easy to use, and studies show that it's the best defense against an attacking bear -- even better defense than a gun.


What is bear pepper spray?

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Bear spray isn't unlike pepper spray that humans use to protect themselves from other humans. The main difference is that bear spray can shoot farther and casts a wider effective area. There are three main ingredients in bear spray:

  • Oleoresin Capsicum (OC): oily residue from hot cayenne peppers. Capsicum is a naturally occurring ingredient that causes a burning sensation when sprayed in the face of an attacker. Food-grade OC is used to give heat to edibles like salsa.
  • Base fluid: mixed with the OC to dilute it. It's typically oil-based to prevent separation from the oily OC.
  • Aerosol propellant: used to eject the ingredients from the can to the threat.

These ingredients are packed into a canister with a trigger and safety to make sure that no unwanted sprays occur. There are six bear sprays currently registered with the Environmental Protection Agency (EPA), and they each have variations depending on what you're looking for. There are four such variations for you to consider when picking out your spray:


  • Spray duration: how long the spray can be ejected, typically four to nine seconds per canister.
  • Reach: how far the spray will shoot, roughly 18-40 feet (5.4 to 12 meters).
  • Weight: Since you'll be carrying it around, you want to consider how heavy it is.
  • Cost: How much do you want to spend to defend yourself from an attacking bear?

When choosing your spray, you need to decide what's most important for you. A blast that shoots 40 feet (12 meters) might make you feel safer from a fast-charging black bear, but it will run out sooner than one that only shoots 25 feet (7.6 meters). There's a group of bear experts called the Interagency Grizzly Bear Committee (IGBC) that made some recommendations for purchasing bear spray in 1999. They believe that a spray that reaches 25 feet (7.6 meters) or more and that lasts for at least six seconds at a minimum of 7.9 ounces is the way to go. Who are we to argue? Out of the six approved brands, only three met these recommended standards, so be sure to read up on brand specifications before you buy some spray and hike fearlessly into the woods.

It's also a pretty good idea that you buy a canister holster to wear on your person. What good is a $45 shot of "Counter-Assault" spray if it's stuck in the bottom of your backpack when Yogi and Boo Boo arrive? You might as well just cover yourself in gravy and lie down on the trail.

Let's say a bear approaches you in the woods. You should make a lot of noise -- blow a whistle if you have one or bang on some pots and pans. Wave your arms above your head to appear larger and more intimidating and back away slowly while avoiding eye contact. Under no circumstances should you ever run from a bear. This will inspire it to run after you and even though they're large, they can hit speeds of up to 30 plus miles per hour (48 kph). When all else fails, reach for the spray, flip the safety off, take aim and fire away. A yellowish cloud will shoot out, and ideally the bear will either get hit straight in the face or run into the cloud. Try and account for wind as best you can -- this is really the only variable unless you're being attacked by multiple bears. If that's the case, try your best to hit both of them.


Is bear spray effective?

Baby bear
Don't spray me. Love me.
John MacDougal/Getty Images

If you're able to hit the bear in the face, you're in business. Most likely the bear will make an instant, confused retreat. It won't knock a bear out, but it will definitely make it forget it wants to eat you. Capsaicin has the same effect on bears that it does on humans. They'll feel an instant burning sensation wherever you hit them, so just like humans, it's best to get them in the face. The eyes, nose and lungs will all burn like fire, causing the mucous membrane tissues to swell.

A face hit almost guarantees temporary blindness and big-time breathing problems. But the good news is that the sting will eventually subside and by that time, either you or the bear are long gone. You have all your limbs in tact, and the bear suffers no permanent damage. The same can't be said about bullets.


What can be said for bullets? They don't always thwart an attack. The U.S. Fish and Wildlife Service investigated human and bear encounters from 1992 to 2005 and found that people who defended themselves with firearms were injured about 50 percent of the time by the bear. People who used the bear spray escaped injury 98 percent of the time, and the few injuries they suffered were far less severe than those in the gun-toting realm. Why? Because it's difficult to stop a bear with a gun and wounded bears are more likely to become even more aggressive.

Another study was performed by Thomas Smith, a bear biologist from Brigham Young University. After analyzing 20 years of bear incidents, he found that bear spray was effective 92 percent of the time, compared to 67 percent for guns. Add to this that you can't bring guns into many national parks, and it seems like the spray is the best way to go.

Research has shown that it takes an average of four direct hits with a bullet to stop a bear [source: Science Daily]. Do you feel like you're a good enough shot to pull this off when a 600-pound (272-kg) grizzly is coming at you at 35 miles per hour (56 kph)? Accuracy isn't nearly as important with bear spray since you're shooting a wide cloud of smoke at your threat. Wind may be an issue, but the Wildlife Service study found that it only affected the shot 7 percent of the time and in each case, the spray still reached the bear. If you happen to shoot yourself or a friend as well, the effect of the bear spray will be the same as human pepper spray and will wear off after a few hours of discomfort.


Lots More Information

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More Great Links

  • "Bear (Pepper) Spray." Get Smart Bear Society. 2008.
  • "Bear Attack Statistics for USA & Canada." 2008.
  • "Bear Spray A Viable Alternative To Guns For Deterring Bears, Study Shows." Science Daily. March 26, 2008.
  • "Bear Spray vs. Bullets: Which offers better protection?" U.S. Fish and Wildlife Service. 2008.
  • "Grizzly mauls, kills a bear 'expert'." Associated Press. Oct. 3, 2008.
  • "Two women charged after alleged bear spray attack at Regina bar." The Regina Leader-Post. August 19, 2008.
  • MacLeod, Casey. "Wednesday night bear spray attacks likely connected, say police." The Regina Leader-Post. August 7, 2008.
  • Medred, Craig. "Spray proves its worth in bear encounters." Anchorage Daily News. April 20, 2008.
  • Nickel, Rod. "Fun Day in the Park ends with attack - UPDATED." The Star-Phoenix. August 25, 2008.
  • Smith, Tom S. "Bear Pepper Spray: Research and Information." U.S. Geological Survey. 2008.
  • Smith, Tom S. "Bear spray - don't leave home without it." Great Falls Tribune. August 28, 2008.