Foxes are the smallest of all the wild mammals in North America. They are also the most widespread, being found from the Arctic tundra to Tierra del Fuego. The fox is a solitary animal and lives in dens and nests, either made by itself or shared with other animals. A family group is called a clan. Fox kits are born in February or March and weigh about one ounce at birth. They have black fur on their heads, backs, tails, and front legs and white fur on their chests, stomachs, and bottoms. Their eyes open at about six weeks old and they start to walk around at about eight weeks old.