Kissing is a big part of human culture. According to ancient cuneiform tablets found in Iraq, humans have been smooching since at least 2500 B.C. Around the world today, many societies share kisses in ...

In the words of Dua Lipa, one kiss is all it took about 21 million years ago. That's roughly when scientists estimate that kissing first emerged in the common ancestor of humans and other great apes.

A couple of years ago, while I was at a dog park and having a great time watching dogs play, I heard a young girl screaming to her mom, "Look, look -- Rosie is making out with Henry!" I turned around ...