COEUR d'ALENE - Compared with a surprised or agitated bear that decides to charge, yelling "No," "Stop," and "Go Away" while firing bursts of a chemical spray seems a bit like bringing judo to a gunfight.

But, for hunters and hikers, when it comes to bear spray, the science must be trusted. Experts say they would rather have bear spray to repel the animal than a gun.

Bears can be slow to die from a gunshot wound, said Chuck Bartlebaugh, executive direct of the Center For Wildlife Information who also oversees the Be Bear Aware campaign.

And, "It becomes very difficult to target" a charging bear with a gun, he said.

He said bear spray was researched and developed by bear scientists. The label must say it's to deter bears, he said. Pepper spray doesn't work.

Bear spray "is effective in a variety of charging situations," he said.

Which is good, because, "There is no one charging scenario," he said.

Bear spray disperses an expanding cloud - with active ingredients Capsaicin and related Capsaicinoids - that will irritate the bear's eyes, nose, mouth, throat and lungs.

"It works long enough for the bear to re-focus on those problems, instead of you," Bartlebaugh said. "It's that refocusing that allows you to back out of the situation."

As bears use their senses in a charge, they end up sucking in more of the irritants.

For example, a charging bear's nose has been shown to work more rapidly gathering information, and it uses its throat and lungs to whoof out sounds.

The spraying must be done correctly to get the bear to run through the orange cloud of suspended irritants. The Capsaicin and related Capsaicinoids act as a barrier.

The bear spray can must be directed downward, and must be held with two hands so it doesn't tilt upwards.

If the bear charges from a close distance, 30 feet or closer, the spray must be focused at the front of the bear until it breaks off its charge.

If it's charging from a distance, from 30 to 60 feet, spray with a slight side-to-side motion.

Bartlebaugh recommends spraying a couple three-second bursts, giving the spray the inertia it needs to travel toward the bear.

"Be prepared to spray multiple times at a charging bear," he said.

Save a little in the can in case the bear zigzags or in case another bear is encountered on the hike out.

He said the active ingredients, the "whoosh" of the spray discharging, and the expanding orange cloud all have been shown to deter a bear.

If the bear makes contact in its charge, the bear spray has been shown to lessen the attack.

He said the number of bear encounters is increasing.

Barb Moore, a wildlife research biologist for the Idaho Department of Fish and Game in Coeur d'Alene, said the huckleberry crop in North Idaho was below average this summer.

So bears are "likely to move a greater distance looking for food," creating the possibility of more encounters, Moore said.

The bears will be looking for their dens between sometime next month and December, she said.

Bartlebaugh said bear spray was not intended for use on bears that are not threatening or charging.

Bears clack their teeth, huff, flatten their ears, slap the ground and move side to side to communicate.

"They want you to back away," he said.

Bear spray is for charging bears.

While avoiding eye contact, but still monitoring the bear's body language, back up. Don't run, he said, or risk triggering the bear's "predatory chase response."

He said that if someone is attacked, that person along with the bear must be sprayed.

In the case of an unexpected close charge, such as a bear entering a tent, spray at its face.

"Make yourself as unattractive as possible," he said.

Information: www.bebearaware.org