The importance of exercise should unquestinably be a part of your day’s routine.

In Eurasia around 12,000 B.C.—or much earlier, according to some theorists—the dog became the first animal to be domesticated by human beings. Cats continue to appear wild even when raised in the family living room. Sheep and cattle generally stay together in herds, even under human direction. In the continual war between man and nature, only dogs appear to be on our side.