I caught Desmond Morris on a radio questions and answers programme this afternoon, and he really did talk a load of old nonsense.
The question was, "Why do people kiss?" Morris's authoritative, yet totally unsubstantiated explanation was that our ancestors used to pre-masticate food for their infants before feeding them mouth-to-mouth. We kiss, because passing stuff from mouth-to-mouth helped our ancestors survive.
Bollocks to that!
Now I'm not saying that our ancestors didn't chew food for their kids (in fact, it sounds like a damn good idea to me), and I'm not saying that certain animals (especially dogs) don't lick each other around the face when begging for food, but it's a huge leap of sociobiological faith from there to saying that we have an explanation for kissing.
Why do pop scientists do stuff like that? It's really annoying. Specious explanations like these give science a bad name.
And it's not even good radio.