I was just watching #austintthebeagle excitedly wag his tail and began to wonder how his evolution from the grey...

I was just watching #austintthebeagle excitedly wag his tail and began to wonder how his evolution from the grey wolf led him to the point that wagging his tail is how he shows that he is happy/excited. I couldn't figure it out, at all. But, then, I thought about how we late-hominids show our happiness by smiling. But all of the other apes certainly do not mean that they are happy when they show their teeth. This realization is certainly going to change to way I interact with other hominids.