A dog was critically injured this weekend when a cougar attacked while the dog was off-leash on the Tellurium Lake Trail near Ruedi Reservoir.

Colorado Parks and Wildlife public information officer Mike Porras confirmed that the department received a report of the attack, which occurred Saturday afternoon.

According to the report, a group was hiking down, with their dog off-leash about 20 feet in front, when they heard a scream. They ran to the scene, and saw a mountain lion holding the dog in its mouth. The hikes startled the predator, which dropped the dog and ran off. The dog is in critical condition with broken skull bones.

Visitors to the area are encouraged to use caution and keep dogs either on leash, or at least under voice command.

“Mountain lions are opportunistic predators,” Porras said, noting that attacking a dog that is separated from humans doesn’t qualify as unusual behavior for a mountain lion. Even if letting a dog run off-leash is legal in a particular backcountry area, “it is far, far safer ... to keep the dog on a leash,” he said.