When it comes to graying, Batteiger said "not all dogs" will develop gray fur but "most will show some signs as they age." The color of a dog's coat can also make a difference—"not in when they ...

The dog, Canis familiaris, is a direct descendent of the gray wolf, Canis lupus: In other words, dogs as we know them are domesticated wolves. Not only their behavior changed; domestic dogs are ...