Scientists decipher dog-tail wags

I found this article on BBC.

Scientists found out a link between wagging dogs’ tails and their feelings. Dogs tend to wag their tails more to the right when they feel happy or relaxed, and more to the left when they are nervous. The movement of a tail gives similar impressions to dogs looking at them.

Although I do not have a dog, I thought there are some people who have a dog and this news might be interesting information for them, so I chose this article. I was surprised that dog’s feeling is different depending on wagging its tail to right or left. I think it is important for pet’s owners to understand their pet’s emotions to make a good relationship with their pet because Animals cannot speak human words. I would like scientists to carry out more research, and I hope people will be able to read animal’s feeling correctly from animal’s behaviors in the future.

Questions:
・Have you ever seen dogs wagged their tail only right side or left side?
・When you communicate with animals, how do you know their feeling?