On May 9th, President Obama signed the National Bison Legacy Act, symbolically declaring the North American bison the national mammal of the United States. The North American bison, mistakenly called buffaloes, once covered the American Great Plains. During the 19th century, settlers killed an estimated 50 million bison for food and sport. Bison populations dwindled to a few hundred but their population has since rebounded to approximately 200,000 living on preserves and ranches. The National Bison Legacy Act does not alter any current bison policy.
For more information, see:
USA Today, "President Obama signs bill declaring the bison the national mammal" May 9, 2016, http://www.usatoday.com/story/news/politics/theoval/2016/05/09/president-obama-signs-bill-declaring-bison-national-mammal/84147012/