National Geographic : 1944 Sep
Ui rational ueograpnhic Society Painting byWalter A.Weber A Pair of American Wolves Rear Their Cubs in .an Alaskan Cave Gray mother will teach her young to avoid traps, poisons, and guns. Like their European brothers, they are members ofCanis lupus. Black and gray arephases of the same wolf. Dog and wolf cross readily. Howl and bark distinguish them, but each can learn to imitate the other. Their tooth and bone structure aresimilar. Modern opinion is that they share a common ancestry.