As Yellowstone opens for its summer season, the national park is asking visitors to make a pledge.

The Yellowstone Pledge is “a personal promise” of 10 actions that visitors can take to better protect themselves and the park itself.

The first item on the list is to “Practice safe selfies by never approaching animals to take a picture.” The park has also posted an article on the “5 Places Not to Pose in Yellowstone.” According to Yellowstone, bison injure more tourists at the park than any other animal.

“It stems from negative behavior,” Yellowstone public affairs specialist Morgan Warthin told Cody Enterprise. “People are getting way too close to wildlife.”

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Visitors who take the pledge also promise to stay on boardwalks in thermal areas, park in designated areas, obey speed limits, recycle, prepare for bears and avoid throwing things in the hotsprings.

Last year, a 23-year-old man slipped off a boardwalk and into a hotspring to his death. Other tourists have been charged or even gored by bison while attempting to take a picture.

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Over the past two years, Yellowstone has welcomed a record number of visitors. Last year, 4.2 million people went to the park and even more are expected in 2017.