Kæledyr
Der er 19 nationalparker i det kontinentale USA, der har gråulve: Isle Royale, North Cascades, Sequoia og Kings Canyon, Yellowstone, Crater Lake, Mount Rainier, Grand Teton, Great Smoky Mountains, Glacier, Voyageurs, Olympic, Denali, Great Basin, Rocky Mountain, Hot Springs, Lassen Volcanic, Glacier Bay, Yosemite og Wrangell-St. Elias.