If you do happen to encounter a bear suddenly and it sees you, try to stay calm and not make any sudden moves. Do not run. You could not possibly outrun a bear; they can exceed 40 mph for short distances. Bear researchers now suggest that quickly climbing a tree is also not a wise way to escape bears, and it may actually incite an attack.

Instead, make yourself visible by moving into the open so the bear will (hopefully) identify you as a human and not something to eat. Never stare directly at a bear. Sometimes dropping an item such as a hat or jacket will distract the bear, and talking calmly (easier said than done) also seems to have some value in convincing bears that you’re a human.

If the bear sniffs the air or stands on its hind legs, it is probably trying to identify you. When it does, it will usually run away. If a bear woofs and postures, don’t imitate — this is a challenge. Keep retreating. Most bear charges are also bluffs, and the bear will often stop short and amble off.

If a brown (grizzly) bear actually attacks, hold your ground and freeze. It may well be a bluff charge, with the bear halting at the last second. If the bear does not stop its attack, curl up facedown on the ground in a fetal position with your hands wrapped behind your neck and your elbows tucked over your face. Your backpack may help protect you somewhat.

Remain as still as possible even if you are attacked, since sudden movements may incite further attacks. It takes an enormous amount of courage to do this, but often a bear will only sniff or nip you and leave. The injury you might sustain would be far less than if you tried to resist. After the attack, prevent further attacks by staying down on the ground until the grizzly has left the area.

Bear authorities recommend against dropping to the ground if you are attacked by a black bear, since they tend to be more aggressive in such situations and are more likely to prey on humans. If a black bear attacks, fight back with whatever weapons are at hand; large rocks and branches can be surprisingly effective deterrents, as can yelling and shouting. (This assumes, of course, that you can tell black bears from brown bears. If you can’t, have someone who knows — such as a park ranger — explain the differences before you head into the backcountry.)

Nighttime bear attacks are perhaps the most frightening, and could happen to even the most seasoned adventurer. In 1996, one of Alaska’s best-known wildlife photographers, Michio Hoshino, was sleeping in his tent on Russia’s Kamchatka Peninsula when a brown bear attacked and killed him. In the rare event of a night attack in your tent, defend yourself very aggressively. Never play dead under such circumstances, since the bear probably views you as prey, and may give up if you make it a fight.

Before you go to bed, try to plan escape routes should you be attacked in the night, and be sure to have a flashlight and pepper spray handy. Keeping your sleeping bag partly unzipped also allows the chance to escape should a bear attempt to drag you away. There are advantages to having multiple tents in case one person is attacked, and if someone is attacked in a tent near you, yelling and throwing rocks or sticks may drive the bear away.

The latest development for campers in bear country is the use of portable electric fences made by Electro Bear Guard (907/232-9758, www.electrobearguard.com) to surround your campsite; a backpacker unit runs on two AA batteries, weighs just two pounds, and costs $280.

Many Alaskan guides, government employees, and others working in wild places carry weapons of some sort; 12-gauge shotguns are a common choice. Visitors to Alaska are unlikely to carry such weapons, and even less likely to know when to use them.

Don’t endanger the lives of bears by heading out into the wilderness with a gun but without an understanding of bear behavior. You have plenty of alternate places to go; the bears do not.

Far too many bears die unnecessarily in Alaska following encounters with humans. Guns are not allowed in several Alaskan national parks, including Denali, Katmai, Glacier Bay, Sitka, and Klondike Gold Rush.

Cayenne pepper sprays such as Counter Assault (800/695-3394, www.counterassault.com) have proven useful in fending off bear attacks in some situations; they’re sold in most Alaskan camping supply stores. These “bear mace” sprays are effective only at close range, particularly in tundra areas, where winds quickly disperse the spray or may blow it back in your own face.

Another real problem with bear mace is that you cannot carry it aboard commercial jets, and most air taxis do not allow it inside an aircraft, because of the obvious dangers should a canister explode. Many floatplane pilots will, however, carry it in the storage compartments of the floats. But be sure to let the pilot know that you have it with you on the flight.

If you do carry a pepper spray on a hike, make sure it is readily available by carrying it in a holster on your belt or across your chest. Also be sure to test-fire it to see how the spray carries. Though they are better than nothing, pepper sprays are certainly not a cure-all or a replacement for caution in bear country. It’s far better to avoid bear confrontations in the first place.

Detailed bear safety brochures are available at Alaska Public Lands Information Centers (www.alaskacenters.gov) in Ketchikan, Tok, Anchorage, and Fairbanks, or on the Alaska Department of Fish and Game’s website (www.adfg.state.ak.us). Two good bear safety books are Bear Attacks: Their Causes and Avoidance by Stephen Herrero and Bear Aware: Hiking and Camping in Bear Country by Bill Schneider.