In preparing for an interview with bestselling author Alexandra Horowitz for my upcoming book, Soldier Dogs, I re-read parts of her intriguing book, Inside of a Dog: What Dogs See, Smell, and Know. In case you haven’t seen it, it’s a must-have for dog lovers who want to gain some insight into how their dogs sense the world.

One of the many fun and interesting parts of the book involves tail wags. With enough research, someone could write a book on the language of tail wags. Horowitz, in fact, states that “It is to science’s great discredit that no one has done a thorough investigation of the meaning of every wag of the dog’s tail.” Anyone need a PhD topic?

She goes on to write that researchers have accidentally discovered that dogs don’t wag their tails symmetrically. “On average, dogs’ wags tend more strongly to the right when they suddenly see their owners – or even anything else of some interest: another person, a cat. When presented with an unfamiliar dog, dogs still wag – more that tentative wag than the happy wag – but tending to the left.” The study she is probably referring to discusses the “striking asymmetries in the control of tail movements,” and shows how the different halves of the brain control different emotions.

But you may not notice this “side bias” motion unless you watch your dog on slow-motion video playback, she says. She highly recommends capturing your dog’s wags on video and playing then back so they’re slowed down. You may be surprised at what you miss in “real life.”

Dogsters, have you ever noticed any propensity for your dog to be left-tailed with some things, right-tailed with others? If you follow Horowitz’s advice and record your dog wagging under different circumstances, please write back and let us know what you find! In the meantime, it would be fun to trade wag stories. Does your dog do those round-and-round wags when she greets you? Has she ever knocked anything valuable off the coffee table with her tail? Does your dog wag at weird times? Let’s swap stories and learn more about this telltale part of a dog’s anatomy.