Science is always providing new information that allows us to interpret the behaviors of dogs, or to reinterpret behaviors which we thought we understood very well-such as the meaning of a dog's tail wagging.
Perhaps the most common misinterpretation of dogs is the myth that a dog wagging its tail is happy and friendly. While some wags are indeed associated with happiness, others can meanfear, insecurity, a social challenge or even a warning that if you approach, you are apt to be bitten.
In some ways, tail wagging serves the same communication functions as a human smile, a polite greeting or a nod of recognition. Smiles are social signals and are thus reserved mostly for situations where somebody is around to see them. For dogs, the wag seems to have the same properties.
Since tail wagging is meant as signal a dog will only wag its tail when other living beings are around-e.g. a person, another dog, a cat, a horse or perhaps a ball of lint that is moved by a breeze and might seem alive. When the dog is by itself, it will not give its typical tail wags, in the same way people do not talk to walls.
Like any other language, tail wags have a vocabulary and grammar that needs to be understood. Up to now scientists focused on two major sources of information, namely the tail's pattern of movement and its position. However new data adds a third important dimension tounderstanding the language of the canine tail.
Movement is a very important aspect of the signal. Dogs' eyes are much more sensitive to movement than they are to details or colors, so a moving tail is very visible to other dogs. Evolution has made tails even more visible, such as tails with a light or dark tip, a lighter underside or a bushy shape.
The tail's position-specifically, the height at which it is held-can be considered a sort of emotional meter. A middle height suggests the dog is relaxed. If the tail is held horizontally, the dog is attentive and alert. As the tail position moves further up, it is a sign the dog is becoming more threatening, with a vertical tail being a clearly dominant signal meaning, "I'm boss around here," or even a warning, "Back off or suffer the consequences."
As the tail position drops lower, it is a sign the dog is becoming more submissive, is worried or feels poorly. The extreme expression is the tail tucked under the body, which is a sign of fear, meaning, "Please don't hurt me."
Just as there are different dialects to a human language, such as a southern drawl or a New England twang, there are also dialects in dogs' tail language. Different breeds carry their tails at different heights, from the natural nearly vertical position common to Beagles and many Terriers to the low-slung tails of Greyhounds and Whippets. All positions should be read relative to the average position where the individual dog normally holds it tail.
Movements give additional meaning to the signals. The speed of the wag indicates how excited the dog is. Meanwhile, the breadth of each tail sweep reveals whether the dog's emotional state is positive or negative, independent from the level of excitement.
As a result, there are many combinations, including the following common tail movements:
● A slight wag-with each swing of only small breadth-is usually seen during greetings as a tentative "Hello there," or a hopeful "I'm here."
● A broad wag is friendly; "I am not challenging or threatening you." This can also mean, "I'm pleased," which is the closest to the popular concept of the happiness wag, especially if the tail seems to drag the hips with it.
● A slow wag with tail at 'half-mast' is less social than most other tail signals. Generally speaking, slow wags with the tail in neither a particularly dominant (high) nor a submissive (low) position are signs of insecurity.
● Tiny, high-speed movements that give the impression of the tail vibrating are signs the dog is about to do something-usually run or fight usually. If the tail is held high while vibrating, it is most likely an active threat.
We can now add another newly discovered, feature of dog tail language that may surprise attentive pet owners as much as it surprised scientists like me. It now appears that when dogs feel generally positive about something or someone, their tails wag more to the right side of their rear ends, and when they have negative feelings, their tail wagging is biasedto the left.
Giorgio Vallortigara, a neuroscientist at the University of Trieste in Italy, and two veterinarians, Angelo Quaranta and Marcello Siniscalchi, at the University of Bari published a paper describing this phenomenon in the journal Current Biology. The researchers recruited 30 family pets.... read more
Published on December 4, 2011 by Stanley Coren, Ph.D., F.R.S.C. in Canine Corner