That dog with the waggily tail may not be as friendly as you think. While most dogs wag their tails to signal happiness and anticipation, that’s not the only emotion that a wagging tail can express, according to E’lise Christenson Bell, a certified veterinary behaviourist. A wagging tail may also indicate that a dog is angry, agitated or annoyed. How can you tell why your dog is wagging his tail? Understanding a little bit about dog anatomy and behaviour can help you interpret the cues that tell you whether you’re dog’s wagging tail is a friendly greeting or a warning to step back.
Anatomy of a Dog’s Tail
A dog’s tail is the end of his spinal column. It is attached to the backbone, though attached isn’t exactly the right word. In fact, a dog’s tail is the hindmost end of his backbone. It consists of six to 23 vertebrae enclosed by muscles that are attached to the vertebrae by tendons. The highly mobile and flexible vertebrae and muscles give the dog an enormous amount of control over how his tail moves. He can lift it, move it from side to side or pull it down to cover his anus and tuck between his legs. In every one of these positions, the tail is capable of many different movements, making it nearly as expressive of emotions as a human’s face.
The Great Communicator
Dogs are not born knowing how to wag their tails, but most puppies learn how to use their tails to communicate by the time they’re about a month old. As they grow, they learn an entire “language” of tail gestures. Some of these seem instinctive and some serve more purpose than simply communicating with others. These are a few of the hints you can use to determine what your dog’s wagging tail is telling you.
If your dog is holding his tail high and wagging it from side to side, he’s probably pretty happy with the world. If his tail is tucked down, he’s feeling nervous and defensive. When his tail is in that position, it prevents other dogs from sniffing him, a sure sign that he’s not feeling particularly friendly.
When a dog is interested in something and curious about it, he’ll hold his tail horizontal. If his tail goes from horizontal to upright and stiff, he’s on the defensive. This is not a good time to approach or challenge him.
Dogs use their scent, which is largely expressed through their anal glands, to mark territory and to announce their presence. When a dog holds his tail high, more of his scent spreads on the air. When he wags his tail, he’s spreading his scent even further. A dog who is uncertain will keep his tail low and tucked to move under the radar, so to speak.
A Matter of Balance
Besides the role that tails play in communication, a dog’s tail is also important to his balance. A long, thin tail helps a dog counterbalance himself when he’s running and has to make a turn, for example. Long, bushy tails may also help a dog keep warm. Many dogs will pull their furry tails over their faces when they lie down in cold weather to keep their heads and ears warm.
By understanding the language of the tail, you can better gauge what your dog, or any other dog, is trying to tell you, and save yourself from potentially dangerous situations.