Scientists seem to have found an explanation for why dogs wag their tails

In general, tail wagging is associated with arousal, either positive or negative, which may be related to associated hormones and neurotransmitters in the animals’ bodies. In particular, researchers have identified an indirect link between oxytocin, or the love hormone, and tail wagging, as well as the stress hormone cortisol, but in the case of the latter, the link is less clear.