Today's useless fact - Why do dogs wag their tails when they're happy?

There are several reasons why a dog wags its tail, and not all of them have to do with being a happy-go-lucky puppy. Since the ancestors of today's domesticated dogs ran in packs, communication -- whether by barking, growling, or wagging tails -- was essential.

A dog with a loosely wagging tail is usually a dog that is friendly or excited. However, a wagging tail is not always a sign of an amiable pooch. An aggressive dog might hold its tail high and wag only the tip, while a submissive or scared dog is more likely to hold its tail low and wag it stiffly.

Some experts believe that a wagging tail is a sign of conflict. When an animal is in conflict, it wants to retreat and advance at the same time. The wagging tail is an indication of this confusion.

When you see a dog wagging its tail, odds are that the dog is in good spirits, probably running after a ball or begging for a treat. However, you should be aware that a wagging tail isn't a definitive sign of a friendly dog; proceed with caution if you think the dog is aggressive. Check out the links in our Dog category for more.