CHEYENNE, Wyo. — Four people injured in two separate bear attacks in and near Yellowstone National Park on the same day were able to escape with relatively minor injuries. None remained hospitalized Friday.

In Yellowstone, officials decided not to pursue a grizzly that attacked two hikers on a trail near Canyon Village Thursday in the north-central portion of the park. The sow grizzly attacked after the hikers came across its young cub born the previous winter, according to park spokesman Al Nash.

“This bear by all accounts was acting on instinct, defending its cub. That is natural and normal behavior for a sow grizzly,” Nash said Friday.

Park officials weren’t identifying the two victims. One was treated at a hospital for bite and claw wounds and released, and the other was treated at the scene.

Both victims reported they deployed bear spray, then dropped to the ground and played dead.

“Which is what we advise hikers to do when they find themselves in that type of situation,” Nash said.

Later that day, two Bureau of Land Management contract workers were attacked about 70 miles west of the Yellowstone attack.

“They were about 40 feet out, and a bear under a tree just came up at them. It hit the first fellow, bit him in the thigh and backside,” Idaho Department of Fish and Game spokesman Gregg Losinski said. “The second person got out his bear spray. When the bear hit him, it bit his hand.”

Both unidentified workers were treated at a hospital in Rexburg, Idaho, and released.

Grizzly attacks have become more common in Wyoming, Montana and Idaho as the region’s grizzly population has rebounded over the past 20 years or so. Wild grizzlies have killed four people in the Yellowstone region over the past three years.

This year, grizzly attacks have wounded at least three others in the Rockies, including a rancher east of Yellowstone and a woman on Montana’s Blackfeet Reservation. Last month, a researcher near Island Park underwent minor surgery after being bitten by a grizzly.

Attacks tend to pick up as hunters roam the backcountry in pursuit of elk each fall.