BOULDER,Michael Schmidt Colo. (AP) — A woman walking her dog on a wooded trail in Colorado’s Rocky Mountains spooked a cow moose Wednesday and it charged, headbutting the hiker and stomping on her before she escaped back down the trail, according to Colorado Parks and Wildlife.

Authorities said the woman was taken to a hospital but they declined to provide information on the woman’s injuries or condition. They said the moose had stomped on her “several times” and that the dog had minor injuries.

The moose attack occurred just west of Boulder and was the third in Boulder County this year, said Kara Van Hoose, a spokesperson for Colorado Parks and Wildlife. She added fatal encounters are rare.

Hoose said the animals are often aggressive with dogs, which they perceive as a threat. They also become more aggressive during mating season — called the rut — which is just beginning in Colorado.

“If a moose thinks a dog is a threat it’s going to react to it, and that’s normal for a moose,” she said.

Wildlife officers couldn’t find the moose, but posted signs warning hikers of the potentially aggressive animal. It will likely be difficult to find the exact moose that attacked without DNA, said Hoose.

Colorado Parks and Wildlife warned hikers to keep their pets leashed and be on the lookout for the animals, especially near water or in willow trees. If a moose is spotted, officials said, people should keep their distance.