YELLOWSTONE NATIONAL PARK, Wyo. (AP) — A pair of wolf pups were fatally hit by a vehicle in Yellowstone National Park after the animals became used to humans and started hanging around a road near their den, park officials said.

The pups were hit at about sunset Tuesday on the road between Tower Junction and the park’s northeast entrance.

The animals were from the Junction Butte pack, a group of wolves that ranges between the Lamar Valley and Tower Junction and is frequently seen by visitors.

Park officials say in recent months some hikers had violated a requirement to stay 100 yards from wolves and approached the pups to take their photo.

After becoming accustomed to people, the pups began coming close to visitors along the road prior to being killed.

Yellowstone had about 80 wolves living in nine packs, according to the latest population count.