Amy, turning back here at home and that bison attack at a state park in South Dakota caught on camera. A bison charging a motorcycle passenger. Diane Macedo has the story. Reporter: This morning, a bison attack caught on camera. Holy . Oh, my god. Reporter: Video shows a woman tossed around by the animal in South Dakota's Custer state park as shocked onlookers watch. She's unconscious. Reporter: The 54-year-old was attempting to approach a bison calf Wednesday. How close does she have to get? Reporter: When an adult bison charged. Oh, my god. Reporter: Animal experts say adult bison can weigh up to 2200 pounds and can be aggressive if provoked. Bison can be really unpredictable. That's the risk with them. They may look calm sitting, you know, right off the path, but they can change in an instant. Reporter: The woman lost consciousness as the bison swung her around. Its horn caught on her belt and jeans. But she escaped serious injury after her pants came off. Oh, my god. It got her. Reporter: Now local sheriffs are reminding visitors to the park, if you see bison, keep your distance. Now, after the attack happened, the bison ran off with the rest of the herd but the local sheriff's office issued a warning about this days before it happened. They say bison occasionally block the road and are advising people if that happens, stay in or on your vehicle and, guy, they also say to remember that in this park, it's their park and we are the guests. Yeah, that is so true. You can get awesome pictures from the safety of your car. As you did when you saw All right. We are following a lot of other