Parks Canada is monitoring a pack of wolves that have attacked and eaten two dogs hiking with their owners near the Jasper townsite.
"This pack is growing up with a lot more interaction with humans," says Saajke Hazenberg, a wolf biologist in the national park.
"Not having negative consequences — and having eaten a few dogs — they associate people with dogs, with food," she said. "This is the start of the habituation cycle we are trying to avoid."
Over the past year the pack has killed two dogs that were on area trails with their owners.
Jasper resident Kirsten Boisvert ran into the wolves on a wooded trail near Pyramid Lake just north of town in early June.
Her dog Kona strayed into the bush and returned with company — a grey wolf.
"My dog was pretty scared," she said. "The wolf was hovering around him and running straight at me. I was a little scared."
Dog owners urged to carry pepper spray
Boisvert, sandwiched between her dog and the wolf, picked up a stick and began waving it.
She managed to back up through the woods to the highway where she and Kona jumped into a passing car.
"This whole time he was pursuing me," she said.
The park, visited by hundreds of thousands of tourists each year, is keeping a close eye on the animals.
Problem wolves are normally tracked with GPS, but staff have been unable to put collars on animals in the problematic pack.
Park officials are urging dog owners to keep their pets on leashes and to carry pepper spray.
"We are just concerned about the whole shift from dogs to people," said Steve Malcolm, with Parks Canada.
"That doesn't happen very often, but wild animals are wild animals," he said.
Ultimately, if the wolves become more aggressive, the park may have to take drastic action, closing certain areas or even culling wolves, Malcolm said.