Age and gray hair ... they go together.

But notably, writes Tara Parker-Pope: "Scientists haven’t found a link between signs of aging in hair and real aging in the body."

I recall reading somewhere that one's hair tends to be inherited from the father's side of the family. My father died at 78 without a single grey hair on his head. Meanwhile, friends my own age who are starting to grey accuse me of using Grecian Formula or Just For Men.

I have a 15-year old black cat who has developed a grey spot on his muzzle, so it's probably not confined to humans.