Updated

A female grizzly bear was captured after going on a predatory spree, killing more than 70 sheep around Montana in a two week period.

The sow slaughtered sheep throughout ranches within a 20-mile radius of Great Falls, Mont. None of the sheep appeared to have been killed by the cub travelling with her, and only two sheep appear to have actually been eaten.

"Sometimes the predatory instinct of grizzly bears just kicks in and they go to killing livestock," Carol Bannerman, public affairs specialist with the U.S.D.A.'s Wildlife Services told FoxNews.com. She explained that it isn't clear why the bear went on the rampage.

"The problem is, once they discover how easy it is to kill sheep in particular, they seldom stop killing [them]."

The depredations occurred at three ranches within eight days. Between June 16 and June 22, some 72 sheep were killed and at least four more were injured. At one site, 50 sheep were killed in two nights.

"She wouldn't go back. Some animals will go back to the location where they have depredated and eat. That did not happen," Bannerman said.

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At one point, wildlife services were able to capture the grizzly cub, place a GPS tracker on it, and released it in the hopes that it would return with its mother.

There was an initial struggle to locate the cub once it had reunited with the sow, however -- so much so, that they had to start a helicopter search.

On June 24, the two were finally tranquilized.

"The sow wasn't in very good shape," Mike Madel, grizzly bear management specialist at Montana Fish, Wildlife, and Parks, told FoxNews.com.

"It was the youngest mother and the smallest cub I had ever found," he continued. "She was four and a half years old and the cub was 32 pounds. Usually at that age they weigh around 50."

When the bears were recovered, researchers saw that the sow had ear tags from 2010, when she was captured by Madel. Grizzly bears can be euthanized if they have previously been captured for depredating. Luckily, the sow had been captured for research purposes, so the team of biologists opted to relocate the two.

The four year old sow and her cub were placed 160 miles from the incident, around Frozen Lake, near British Columbia.

The tracking and relocation of the animals was a collaborative effort between the  U. S. Forest Services, Montana Fish, Wildlife, and Parks, U.S. Fish and Wildlife Services, and U.S.D.A. Wildlife Services.

Even though in a recent depredation incident, a male the bear was euthanized, Madel said that wildlife departments handle incidents on a case by case basis.

"We've moved towards fast recovery because we've protected the female grizzly population that grows over time," Madel remarked.

Grizzly bears are currently listed as threatened on U.S. Fish and Wildlife Service's Threatened and Endangered Species List, but Madel says that at a growth rate of three percent, they could soon be removed from the list.

"Going through that capture event usually makes them wary of other people. She's less likely to do this again."