Park rangers of Yellowstone National Park regularly hand out precautionary flyers to tourists visiting the expansive wilderness. The warnings are common sense: don’t run towards the animals, don’t shout at the animals, and don’t attempt to steal the animals. Ok, maybe not that last one.

One such notice is illustrated with a man being gored and flung into the air by a bison, cautioning visitors to not come within 22 meters (72 feet) of the cattle-like herbivore. Yet the message doesn’t seem to be clear enough as two people have been injured by bison at Yellowstone in the past three weeks.

The latest attack saw a 62-year-old Australian man flung several times into the air by an angry bison earlier this week. Park officials report that a crowd had formed within 1.5 meters (5 feet) of the bison at rest. As they were taking photos, the incensed bison charged towards the man, repeatedly goring him on its curved horns as it threw him into the air. The unidentified man was flown by helicopter to a nearby hospital, where he was treated for serious injuries and released the same evening.

Last month, a bison gored a 16-year-old Taiwanese girl as she posed seemingly too close to the animal for a photo. Sustaining serious injuries, she was also quickly transported to a hospital.

Maybe it’s their hefty size, maybe it’s their presumed docility, but the Bison bison is not always the slow and steady type. The average male American bison can weigh up to 900 kilograms (2,000 pounds) and, when aggravated, can reach speeds of 48 kilometers per hour (30 miles per hour). You wouldn’t want that charging towards you.

“There’s just a lot of people around, and the temptation is there when a bison looks calm,” said Yellowstone spokeswoman Traci Weaver to Yahoo News.

As a tourist attraction, it’s easy to forget that the animals of Yellowstone Park are in their natural environment and will behave as such. A recent “bear jam” at Yellowstone saw a mother protect her cubs from a crowd of park visitors as the bears attempted to cross a bridge.

With an approximate 24% increase in park visitors over the past 15 years, Yellowstone park rangers are stretched to police the tourists and protect the wildlife, which is why the rangers urge tourists to exercise common sense. Unfortunately, it seems common sense isn’t all that common.