At Minneopa State Park, layers of soil and artifacts show that people hunted bison here for thousands of years. A thoracic vertebra supports muscles in the bison's hump. From 6000–4000 years ago, a stone point indicates people may have hunted bison here with darts or spears. From 2200–1700 years ago, pottery pieces suggest families cooked and camped here. From 1200–300 years ago, another stone point suggests hunters used bow and arrows to hunt bison. From 170–140 years ago, people slaughtered millions of bison for profit, hides, and sport, and wild bison disappeared from Minnesota. Today, conservation protects the herd, and state parks protect and use bison to help manage the prairie.