Native Americans and early trappers and settlers traded fur for food, supplies, and European goods. In Europe, animal pelts were prized for warmth, especially for beaver felt hats, which were an expensive status symbol. Fur companies, such as the Hudson Bay Company, established forts and fur trading posts to consolidate trading activities and compete in buying furs. Although much of the fur trade was based on the value of beaver pelts, bear skins and oil also were a common trade item in exchange for firearms, ammunition, cloth and liquor. At times, a black bear skin could be worth as much as five beaver pelts. The number of bear pelts exported rose from the late 1700s until 1830 but diminished as bear populations declined. A number of NPS sites commemorate the fur trade, including Fort Union Trading Post and Voyageurs National Park.