Aggressive grizzlies have prompted officials in Denali National Park and Preserve to close trails and parking lots.
The Savage Alpine Trail, the Savage River Loop Trail and both Savage River parking lots were closed indefinitely as park wildlife technicians tried to teach a bear in the area to avoid approaching humans. The park has also stopped issuing backcountry permits for the Savage River area.
The small grizzly early in the week charged vehicles near the Primrose area and chased visitors near Savage River along the Denali Park Road.
The same bear also charged hikers on the Savage Alpine Trail on Wednesday and consumed two candy bars and bottles of soda from a daypack one hiker threw as a distraction.
Dave Schirokauer, resources and science team leader for Denali National Park, called the situation "very serious" because the bear was rewarded for aggressive behavior and may have learned to associate humans with food.
Wildlife technicians hope to find the bear and lure it into a similar scenario, but instead of providing treats, they plan to fire paint balls, beanbags and rubber bullets at the animal to make it wary of people.
"The bears of Denali are wild creatures, free to behave as they wish. If annoyed, these solitary animals can be very dangerous to intruders," park officials said in a statement.
In another bear encounter Thursday, a grizzly sow with cubs bit a park bus driver on the left calf as he was hiking in thick brush near Mile 8 of Denali Park Road.
Phil Buchanan said he heard one of the cubs shriek and the mother grizzly charged him almost immediately.
Buchanan said he stood his ground and the sow dived at his leg. He curled up and played dead, then remained there for five minutes. Buchanan was also injured below his left ribcage.
He hiked about two hours before reaching the main park road and flagged down a visitor in a vehicle.
Buchanan was treated for his injuries at the Denali Canyon Clinic and later transferred to a hospital in Fairbanks.
Schirokauer said the sow was likely surprised and threatened and was acting to protect her cubs.