The Language of a Dog's Tail Wag: Right Is Good, Left Is Bad [Video]

Seems there's more to a dog wagging its tail than a simple twitch of ecstasy. Scientists have deciphered the language of the wag, and it can tell us a lot about a dog.

According to the new findings, tail wagging, and the direction it tends towards, is an extension of which hemisphere of the dog's brain is being used. A right-asymmetrical tail wag indicates positive feelings, while a left-asymmetrical tail wag means, you guessed it, the dog isn't feeling too good about the current situation.

"The direction of tail wagging does in fact matter, and it matters in a way that matches hemispheric activation," says Giorgio Vallortigara of the Center for Mind/Brain Sciences of the University of Trento.

"In other words, a dog looking to a dog wagging with a bias to the right side-and thus showing left-hemisphere activation as if it was experiencing some sort of positive/approach response-would also produce relaxed responses. In contrast, a dog looking to a dog wagging with a bias to the left-and thus showing right-hemisphere activation as if it was experiencing some sort of negative/withdrawal response-would also produce anxious and targeting responses as well as increased cardiac frequency. That is amazing, I think."

The telltale of tail wagging might be subconscious, but the researchers point out it could still be a useful lexicon for humans to know.

"It could be that left/right directions of approach could be effectively used by vets during visits of the animals or that dummies could be used to exploit asymmetries of emotional responses," Vallortigara says.

So remember, the next time your dog wags its tail, listen carefully, it just might be trying to tell you how it actually feels.

The full published study detailing the findings can be found in the journal Current Biology.