Run or fight. The choice comes up often in life.

Now it's a decision to consider if you meet an angry mountain lion.

Wildlife officials for decades have advised hikers, hunters, cyclists and others to fight back if they encounter a threatening mountain lion. Make yourself look bigger, they advise, and arm yourself with anything handy: fishing rod, fence post, pocket knife or walking stick.

Now UC Davis researchers, after analyzing more than a century of cougar attacks, say it might be better in some cases to run instead.

"Running seems to reduce injury," said UC Davis psychology professor Richard Coss, the study's lead author. "We're not saying holding your ground doesn't work. It just looks like it might be better to run in certain circumstances. Think of it as adding information."

Coss specializes in predator-prey interactions. His co-authors are three wildlife experts at UC Davis and Kathy Etling, author of a 2004 book on mountain lion encounters.

Published in the peer-reviewed journal Anthrozoos, the study analyzes 185 human encounters with mountain lions, dating to 1890, from throughout North America.

Their source material includes media accounts of mountain lion attacks as well as official government reports. The review is the first of its kind, Coss said.

The researchers dissected the disparate accounts to pull out useful information, such as age of victims, their group size, body posture, whether they ran or stayed, made noise or fired a gun.

They found that the likelihood of escaping injury increased if two or more people were present, and that bending over or crouching is a bad thing to do. This is consistent with the advice typically given to outdoor lovers today.

Making noise had no effect, unless someone fired a gun, which often startled the attacking cougar and sent it running.

More surprisingly, the study found that half the victims who ran from cougars avoided injury, compared with 26 percent who stood their ground.

The important thing, Coss said, is that the person must be able to run without suggesting injury or weakness. That requires a snap assessment of surrounding conditions to assure a smooth, flat, safe surface to run on.

Running also might not be smart for a group, because anyone who falls behind is more likely to be attacked, especially children or the elderly.

Coss said the study doesn't contradict current advice – "it complements."

"You have to really assess right away where you are and is there a chance you can escape," he said. "These cats, like wolves, are very good at detecting any type of limping or any irregularity in your gait."

Mountain lion experts say they will ponder Coss' findings as part of continuing efforts to understand mountain lion behavior. Meantime, they hold to their usual advice: Stand your ground, look tough, plan to fight back.

"The next time I encounter a mountain lion that appears it is attacking me, I will probably stand my ground and behave aggressively toward the animal," said Ken Logan, a mountain lion expert at the Colorado Division of Wildlife.

Logan has studied cougars in Colorado, California, New Mexico and Wyoming. He's seen wild mountain lions "a few hundred times" and been charged twice.

In each case, Logan stayed and postured as if ready to fight. Each time the cougar turned and walked away after charging within 10 feet. Only seconds elapsed in each case.

He noted it would be rare to find ideal conditions to flee a mountain lion.

"They are much faster than a human being," he said. "When I do encounter them, it is extremely rare that I encounter them on flat terrain with no snow."

Coss notes that modern-day Americans have limited evolutionary experience with mountain lions because we've inhabited the continent for only a few hundred years.

But deer, a cougar's primary food, have much more experience. So Coss and his co-authors also explain how deer behave around lions. They use both tactics.

Sometimes deer hold their ground, snort and stamp their feet. Sometimes they trot away with a slow, high-stepping "almost ballet-like" walk that has rarely been observed. This seems designed to telegraph that the deer is agile and fast – that the cougar will have to work for this meal and maybe even take a risk.

Cougars don't like to do that, said Tim Dunbar, executive director of the Sacramento-based Mountain Lion Foundation. They typically kill by ambush, surprising their prey by attacking from behind.

Most highly publicized cougar attacks happen this way. One well-known example is the 1994 case of Barbara Schoener, an extremely fit distance runner jumped from behind by a cougar on a trail at Auburn State Recreation Area.

In short, most victims never see the attack, so they have no choice about what to do.

The good news: Few people will ever have to worry, because even sighting a mountain lion is rare.

California has reported only 14 cougar attacks on people in the past 120 years, said Doug Updike, who oversees mountain lion programs at the state Department of Fish and Game. Six people were killed, including Schoener.

Even though more people are spending more time living and playing in mountain lion habitat, problems seem to be decreasing.

One measure is the permits issued by Fish and Game allowing property owners to kill problem mountain lions that threaten people or livestock. The permits declined from 331 statewide in 1995, the peak year, to 192 in 2007, the most recent data available.

Maybe lions have learned it's better to avoid us.

"The lion's tendency is to hide and hope you go away," said Updike. "They don't like us. We probably smell bad. We certainly act in strange ways. We just do not normally register as a prey item."

Call The Bee's Matt Weiser, (916) 321-1264.