A large male bison ran at a 65-year-old man in Yellowstone National Park, Wyoming. The animal weighed about 900kg. It hit Carl Isom-McDaniel with its head and threw him into the air. The attack happened on Friday evening near Yellowstone Lake.

The man and his grandson stopped to take a photo of the bison. The animal stood up and ran after them. They tried to run away through some trees. The bison caught the grandfather and hit his hip with its horn. He hurt his leg and other parts of his body. He stayed awake, and people took him to a hospital.

Many people visit Yellowstone in summer. July is also the time when bison mate, so male bison may act in ways people do not expect. Park workers say visitors must stay at least 23 metres from bison. They also say people must not go near a bison to take a photo. The park may give more information about the man and the attack later.