I am referring to domestic cats and I think we have to be very specific about the meaning of a “wagging tail”. It might not mean the same thing to everybody and there are subtle differences in tail movements. We need to be clear because I want to answer the question precisely and not waffle about various feline tail movements and what they mean.
I take feline wagging tail as to mean a tail that moves from from its base (i.e. the whole tail moves) left to right more or less horizontally within certain tolerances. That’s what it means when dogs do it and I will take that meaning when answering the question. Dogs wag their tails when experiencing a range of emotions including when they are happy or expecting something good to happen.
The best answer as to why cats wag their tails comes from Dr Desmond Morris and you may know his enlightened analysis. I’ve seen cats do this myself. I’ll set the scene. Your cat is in the backyard or perhaps inside the home looking out the window. The tail moves from left to right (perhaps along the ground) while they stare intently at something. It almost looks as if they are irritated by something and that the tail wag is an expression of that irritation.
And the word “irritation” is not too far removed from what is happening. The conspicuous tail wagging in cats is a social signal indicating acute mental conflict. It is a part of feline body language. It can be employed between one cat and another. In a hunting scenario, tail wagging is a physical manifestation of the cat’s decision-making process which is in the balance. As the tail wags from left to right so the mind is also telling the cat to do something and not do it: to attack or stay back. The two are in harmony: the mental process and the physical action which mimics the mental process.
Some more of cat body language:
- Defensive cat body language. A good example on video.
- Most cats are highly sensitive to human body language
- Why do cats do the crab walk?
Dr Morris says that this physical expression of a cat’s mind being in conflict and in balance between two decisions comes from the use of the tail as a balancing tool. When a cat is walking along a precarious path, perhaps on a branch or a wall, the tail helps to keep them balanced to stop them falling off. We know that the feline tail is a balancing tool which is why it is longer in cats who need it more than those who need it less. I’m referring to the snow leopard as a classic example, a wild cat species which has the longest and most impressive tail of all because they hunt at speed on 40 degree rock faces chasing blue sheep.
To recap, feline tail wagging is an indication of a cat in some sort of mental conflict about decision-making. There may be other emotions present which overlay that fundamental feeling. It does not always occur when cats are hunting. I believe that it may happen when a cat is interacting with their human companion or as mentioned another cat. Perhaps in the latter scenario the cat is trying to work out whether to be hostile towards a cat.