THE BLOG
11/07/2013 05:07 pm ET Updated Jan 23, 2014

Wag This Way: Left or Right Offers Insight

I just got back from the Association of Professional Dog Trainers conference, where one of the seminars I presented centered on the lesser known aspects of canine body language. Among other things, I discussed a study about tail wagging that had been done at Bari University in Italy.

The study involved 30 mixed-breed dogs between the ages of 1 and 6. There were 15 intact males and 15 non-oestrus females. These were family pets, by the way, whose owners had agreed to participate. The dogs were put into narrow, box-like structures with cameras that would track not only which direction their tail wagged, but the precise amplitude. There was a slat at the front of the box through which the dog could see out. (Imagine one of those movies where the character knocks on a door in a seedy neighborhood and the doorkeeper slides the slat open to ask for the password.)

Each dog was presented with a stimulus for one minute, rested 90 seconds, and then saw another stimulus. (The test lasted 25 days with 10 sessions per day.) There were four different stimuli: the owner, an unfamiliar person, a cat, and a dominant unfamiliar dog, who happened to be a large Belgian Malinois. The results were interesting, to say the least. The dogs' tails wagged to the right for the owner (that's the dog's right, by the way), the unfamiliar person, and the cat. Predictably, the widest wag was for the owners, the next widest for the unfamiliar person, and the narrowest for the cat. But when presented with the Malinois, the dogs' tails wagged to the left.

Why would that be? We know that the left side of the brain controls the right side of the body, and vice versa. The anterior of the left hemisphere is associated with feelings of love, attraction, and safety, so it makes sense that a dog's tail would wag to the right for their owner and others for whom the dog felt positive feelings. The right anterior hemisphere, however, is associated with fear and withdrawal, among other things. When the dogs saw the dominant Malinois, those left directional tail wags were telling a tale, and it wasn't a happy one.

The study is fascinating enough on its own, but now the researchers have published a new study in the journal Current Biology. Building on the directional wag theory, they wondered whether other dogs would be affected by a dog's tail wagging to the right or to the left. Would they know the dog was feeling friendly, or not wanting to be approached? As it turns out, yes, they did! They found that dogs who viewed a dog wagging to the right (the warm, fuzzy, left-hemisphere activated response) would show a relaxed response. In dogs who saw a left side wag (produced by the negative/withdrawal brain function), though, there was increased anxiety and even an increased cardiac response.

The research team posits that the directional tail wags might effectively be used to advantage during vet visits or that dummies could be used to elicit positive responses from dogs. Interestingly, during the seminar where I mentioned the tail wag study, I also discussed what I call the Robodog Study, where a robotic dog was used to gauge the response of other dogs to a short or long, wagging or still tail. Canine body language is such a fascinating subject, and these studies only touch on, well, the tail end of it.

For the full story, check out the DVD of my full-day seminar Talk to the Paw: Understanding What Dogs are Saying--and What We're Saying to Them. In the meantime, watch your dog's tail when he meets new people and other dogs; you just might learn a little bit more about his likes and fears!

Nicole Wilde is a canine behavior specialist and author. Visit her website nicolewilde.com.
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