The theory behind why dogs tail wags is that they are happy but that is not true. Dogs use their tail to communicate. Some scientists have figured out what some of the tail wagging means. Scientists do not know why dogs tend to wag their tails a lot. They also wonder if the tail wagging is even under their control. 

Wagging tails is a common behavior. Ethologist Silvia Leonetti from the University of Turin in Italy says that many dog behaviors remain a scientific enigma. An Ethologist is someone who studies animals’ behavior.  Lenonetti and her team have read many studies about why tails wag while doing their study and what parts of wagging we do not understand. They hypothesized how this behavior started. They suggested tail wagging placates for a human need for rhythm or the tail wagging comes from traits.

Canine cognition Emily Bray of the University of Arizona in Tucson that the dog wagging its tail because it is happy narrative is more complicated than it seems. Instead of looking at the wagging tail from a human’s point of view, she is looking at it from an animal welfare point of view. She thinks that it could help humans understand their behavior much better. For example, a tail wag to the right means the dog is curious and a tail wag to the left is uncertain.