The most dangerous animals in Yellowstone National Park are not grizzly bears or mountain lions, but rather bison. And it’s largely the fault of people getting too close and taking pictures. 

Cellphone cameras have a large role to play in five dangerous bison encounters in 2015 at Yellowstone that left several people with critical injuries, according to a new report by the Centers for Disease Control.

Between 1983 and 1985, the park saw 33 bison-related injuries. Those numbers have drastically decreased, but the number of dangerous encounters could still be decreased. Out of the five incidents last year, two were gored and three were tossed into the air. 

Those attacks could have avoided, researchers say, had the visitors paid attention to warning signs urging hikers to remain at least 75 feet away from a bison. Three of the people sustained injuries while taking photographs at a distance of 3-6 feet, including two that turned their backs on the animal to take a selfie. 

“The popularity of smart phone photography with its limited zoom capacity and social media sharing of selfies might explain why visitors disregard park regulations and approach wildlife more closely than when traditional camera technology was used,” the report states.

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Watch this classic bison attack at Old Faithful in the video below:

Photo credit: Dreamstime