You're at a friend's house and along comes her collie, Baby, wagging her tail. Good girl! You bend over to pat her and are rewarded with a growl. What went wrong?
"It is so important for people to realize that a wagging tail does not equal a dog that is friendly or wants to be petted," says E'Lise Christensen Bell, veterinarian and board certified veterinary behaviorist at Veterinary Behavior Consultations of NYC. "It can, but you are much better off looking at the entire dog. If there are stiffened muscles, dilated pupils, tense facial muscles, or ears pinned forward or back, these are signs that you should back off."
Dogs use their tails to communicate strong emotions such as agitation, annoyance and anger as well as happiness. A person can get bitten by a dog that's wagging his tail because he read the signs incorrectly. And make no mistake, there is a science to tail wagging.
Dogs have been wagging their tails since...well, there have been dogs. These furry masses of bones serve multiple purposes. The original purpose of the dog's tail was for balance. It prevents him from toppling over as he makes sharp turns while running or swimming. The tail also balances him when walking along narrow structures, climbing or leaping. Over time, the tail adapted itself to playing a vital role in communication, particularly when a dog is just walking or standing around.
Puppies don't come right out of their mom's womb wagging their tails. The majority of them don't begin wagging until they are about a month and a half old when they have a need to communicate with their litter mates or mothers.
For example, if there's too much "rough-housing" between the pups, one of them might wave their tail like a white flag to signal a truce to its littermates. As they grow, they wag their tail to beg for food from the adults in their canine family.
Next, we'll look at what the various tail positions mean.