Dogs don’t always wag their tails when happy

By Casey Frye, CCNN Writer

puppy tail
Is this little guy happy to see you? It’s all in the tail!

We’ve all been told once or twice in our lives that a dog’s tail reveals a lot about how it feels. When it’s tucked between trembling legs, the canine probably feels afraid. When it’s wagging away rapidly, chances are the pooch is really excited. At least, that’s what we think. However, new research from the University of Trento says it all depends on the direction it’s waving.

“It is very well known in humans that the left and right side of the brain are differently involved in stimuli that invokes positive or negative emotions,” said professor Giorgio Vallortigara, a neuroscientist from the University of Trento. “Here, we attempted to look at it in other species.” As you can imagine, the researchers couldn’t just ask the canines to fill out a survey and report how they felt, so the scientists got creative.

They put the animals in a room, measured vital signs like heart rate and breathing, and had the animals watch TV. Professor Vallortigara said: “We presented dogs with movies of dogs – either a naturalistic version or a silhouette … and we could doctor the movement of the tail and present the tail more to the left or right.” When the creatures watched another dog wagging their tails to the right (from the on-screen dog’s point of view) they remained perfectly calm and otherwise normal. However, when the animals watched another dog’s tail wag to the left, their hearts began to race and they appeared to be really nervous about something. Wow, is this some sort of secret dog language?

According to the researchers, it more like a sign of distress dogs learn to recognize throughout their lives. For example, if they went into a room with a bunch of right tail-wagging dogs and had a good time, they probably associated that direction with fun. On the other hand, if the pooches saw a bunch of left tail-wagging buddies and discovered something scary, they probably learned left meant nervous.

The researchers say this information should be particularly useful for pet owners and trainers, who need to understand their dog’s emotions well.

Featured image courtesy of Rupert Morris on Flickr. Image of happy pup courtesy of bullcitydogs on Flickr.