Story highlights "I just thought I was going to die," 12-year-old survivor says

Bear attacks have increased over the past century, a study found

Lone male bears hunting people are more dangerous than mothers with cubs

This is the time of year when bear encounters are more common, an expert says

Bears rarely attack humans unless they feel threatened or territorial. But a 12-year-old girl jogging in Michigan is among the latest victims in a spate of bear attacks that have left seven people mauled in five states since Thursday.

Abby Wetherell was out on her nightly jog when she was ambushed by a black bear Thursday outside her home in Cadillac, Michigan. She tried to run at first, but, "It just took me down," she told CNN's Piers Morgan Live.

"It clawed me and it was growling," she said. "It was scary."

Eventually, she said, she played dead, hoping it would go away. It did, but not before inflicting cuts and scrapes to her face and deep gashes on her legs that required dozens of stitches.

"I just thought I was going to die," she said. "It was very terrifying."

Abby Wetherell, 12, says she finally got the bear that attacked her to go away by playing dead.

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After the bear left, Abby ran toward a neighbor's house, screaming for help. The bear came after her once again, but neighbors were able to scare it away, she said.

Her father, Chris Wetherell, heard her screams and ran out of the house with a gun, but the animal was gone by then, he said.

Authorities also reported attacks in Alaska, Colorado, Wyoming and Idaho.

The Michigan incident was an anomaly, officials said. Michigan has an estimated black bear population of 8,000 to 10,000, but only about two bear-to-human incidents a year, said Ed Golder, a spokesman for the state Department of Natural Resources.

Wildlife officials are running tests on a bear they killed to see if it's the same one that mauled Abby, Golder said. The bear was killed two miles from the Wetherell home.

"Black bears are generally fearful of humans and will usually leave if they become aware that people are present," the department says.

Bear attacks on the rise

Attacks by bears have risen as human populations have grown, according to a study published in the Journal of Wildlife Management in 2011.

The study found that between 1900 and 2009, 63 people were killed in 59 incidents in Canada and the United States.

"Each year there are millions of interactions between people and black bears with no injuries to people. So while the risk is low, it does exist," University of Calgary professor emeritus Stephen Herrero, one of the authors of the study, said at the time.

In 88% of cases, the bear was exhibiting predatory behavior; in 92%, the bears were males.

"The common belief that surprising a mother bear with cubs is the most dangerous kind of black bear encounter is inaccurate, the University of Calgary said in a summary of the study . "Instead, lone male black bears hunting people as a potential source of food are a greater cause of deadly maulings and related predatory attempts. The study also found that fatal attacks do not typically involve bears that are familiar with humans, although some fatal attacks did."

The study also found that bears that have previously killed people are more likely to attack again, traveling in a party of two people or more is safer, and human food and garbage attracts bears.

The study did not determine why population growth is correlated with more bear attacks. But Herrero said the suspicion is that more people are "pursuing recreational and commercial activities in black bear habitat."

But the study also found that fatalities are more common in Canada and Alaska, despite there being fewer people and less contact with bears than in the lower 48 U.S. states.

Other recent incidents include:

Alaska: Hunter mauled

A hunter mauled by a bear in Alaska survived 36 hours in the remote wilderness before rescuers found him using night-vision goggles, the Alaska National Guard said Saturday.

The man, who was part of a guided hunting party, was attacked about 35 miles north of Anaktuvuk Pass. Helicopter rescue teams tried to reach the man several times but had to turn back due to dense fog and weather, the Guard said.

The hunter suffered significant blood loss but was stabilized by a medical professional who happened to be in another hunting group, the Guard said.

"The pararescuemen credit him for saving the man's life. He provided expert care with limited resource for several hours, ultimately stabilizing, warming and rehydrating the victim," Air Force Master Sgt. Armando Soria said.

Around 3 a.m. Saturday, a helicopter managed to land at the scene, with crews using night-vision goggles to aid in the operation, the Alaska National Guard said.

The man was in stable condition.

Colorado: Camper bitten

A bear clawed its way into a tent and bit a sleeping camper on her arm Thursday night, CNN affiliate KCNC reported.

The woman suffered puncture wounds but was not seriously injured. She called for help, and the bear ran away, KCNC said.

Wyoming: Hikers attacked

Two hikers at Yellowstone National Park were injured Thursday after the encountered a female grizzly bear and a cub. The sow charged the hikers, leaving claw and bite marks on one, park officials said.

The sow and cub left after the hikers sprayed their cans of bear spray.

"Yellowstone bear biologists say the sow's behavior is consistent with purely defensive actions taken after a surprise encounter with people," the park said in a statement. "This was the first report of any bear-caused human injuries in Yellowstone this year."

The park requires visitors to stay 100 yards away from black and grizzly bears and advises hikers to walk in crowds and make noise while on the trail.

Idaho: Researchers assaulted

Two habitat technicians collecting data in Shotgun Valley, Idaho, were injured Thursday when a grizzly bear charged, the Jackson Hole Daily reported.

The bear knocked both men to the ground, biting one researcher on the thigh and backside and the other researcher on the hands, the Daily said.

One of the men used his bear spray, and the grizzly fled the scene.

Why the attacks?

"The reason why we're having bear attacks now is because we have vacationers out in the areas where bears live," said Tom Stalf, CEO of the Columbus Zoo. The bears are "out foraging and looking for food."

Stalf said the migration of humans is another reason for more bear encounters.

"It's called urban sprawl," he said. "As we vacation and we move out of the cities and into the country, we're going to cross paths with different types of animals."

But Harry Reynolds, vice president of the International Association for Bear Research and Management, said sometimes it's just luck.

"I think the recent attacks are circumstance and not any larger outside issue weighing into the attacks," he said. "In past years in Alaska, when there are berry failures, the bears may be more aggressive in looking for food. But this year was a good crop. I really think the recent bear attacks are just circumstance -- people in the wrong time at the wrong place."