Glacier National Park temporarily closed the Granite Park area and trails leading to it because of grizzly bear activity late Sunday and all day Monday.

But Tuesday morning, the Highline, Loop, and Swiftcurrent trail (from Swiftcurrent Pass to Granite Park Chalet) were reopened after no bears were spotted on Monday, the Park said in a release. The Granite Park backcountry campground remains closed.

On Sunday, the park received three separate reports in quick succession of grizzly bears huffing, drooling, shaking heads, and walking visitors back off of trails. It is uncertain whether it was one bear or more, the park said

Bears can respond aggressively in defense of themselves, a food source, or cubs, the Park said.

On Monday morning, park staff hiked to the area to observe bear behavior and conduct hazing activities as appropriate, but no bears were located — just signs of digging that included evidence like scat, disturbed hillsides, and overturned rocks.

The signs of foraging were dispersed over a wide area and no evidence was found of a specific carcass or other food source that the bears were protecting.

The trails remain posted for “bear frequenting”, meaning that recent repeated observations or confirmed reports of bear sign in short intervals exist in those areas.

Facilitated by the Park’s free shuttle services, nearly 1,000 people hike the Highline Trail on a daily during the summer months, according to a 2017 study.

Most folks hike the 11-plus mile route from Logan Pass, down the Highline Trail to Granite Park Chalet and then down to the Going-to-the-sun Road via the Loop Trail.

Grizzly encounters on those trails is not uncommon — the area is excellent grizzly bear habitat.

People can monitor trail status by visiting the park’s trail status webpage.