Animal communication can be defined as the exchange of information between animals through various means that may have an effect on the immediate or future behaviour of another animal.
A dog may wag its tail for a person or another animal, even a passing butterfly but when by itself will simply not wag its tail indicating that tail-wagging is meant as communication or language.
However like any interpretation of communication behaviour you must be careful NEVER to take a small part of display in isolation.
Tail wagging in dogs is a simple behaviour (as regards neurological involvement) but from a functional point of view it is just so complex. Tail wagging could mean any of the following;
It has long been assumed that when dogs wag their tails that they are happy and friendly. But approach a dog that is sending you warning signals to stay away and you just might get bitten!
Understanding more about the positioning of the tail can help understand what the dog is trying to communicate. Movement of the tail is also important as dog’s tails have evolved to be seen, they can have bushy or white undersides or black tips at the end of the tail. Dogs cannot see colour like humans do but they understand movement and it’s meaning.
A slow wag, held at half-mast can mean the dog is feeling insecure with a faster, broader wag being closer to ‘I’m friendly’ wag especially if the back end of the dog is moving as well.
A highly held tail slowly moving (possibly only the tip) can mean the dog is going to do one of two possible things; fight or flight. This tail held high can mean the dog is threatening or sending a warning to back off.
A middle height tends to depict relaxation and a lower tail can mean the dog is feeling anxious or worried.
It is important to understand that different dog breed may have different tail shapes such as spitz breeds that have their tails curled over their backs or even no tails at all. This can make communication between dogs a bit more difficult but not impossible.
How dogs use meta-communication
Gregory Bateson an anthropologist referred to meta-communication as “communication about communication.” It’s mainly used to depict a secondary form of communication so to differentiate the smaller subtleties in communication that can make a world of difference.
Meta-communication is an important factor in influencing the future and current actions of another dog. You may see your dog pinning another dog to the ground, baring teeth or growling during play and some owners become worried and may want to step in and stop the play. But most dogs with good social skills know that when they see meta-signals such as a play-bow and tail wag that subsequent ‘aggressive’ gestures are part of the game – social animals know when they are role playing rather than being serious.
Meta-signals such as the play-bow have also been described by Patrica McConnell as ‘A pause that refreshes’. This pause allows the dogs to manage emotional arousal especially in dogs that have just met.
Vallortigara et al done a recent study into canine body language and discovered that when dogs feel fundamentally positive about something or someone, their tails wag more to the right side of their rumps and when they have negative feelings, their tail wagging is biased to the left. 30 mixed breed pet dogs were shown various stimuli, including an aggressive dog and their owner. When the dogs saw their owners, their tails all wagged vigorously with a bias to the right side of their bodies. When the dogs looked at an aggressive, unfamiliar dog their tails all wagged with a bias to the left side of their bodies. Thus when dogs were attracted to something tails wagged right, and when they were fearful, their tails wagged left. This left or right tail wag must be viewed from the point of view of the dog as if you were looking in the same direction as the dog.
However it is important not to become obsessed with the idea that tail wagging (or lack thereof) is the way to a dog’s soul. Communication displays among social animals especially are full of detail and a wide range of actions for a reason – one being that this helps to change the meaning of a particular part of display when used in differing and changing situations so as to increase the animal’s ‘vocabularly’.