Why do we clap?

Indeed Why do we clap?

If aliens landed at a concert, lecture or show they’d be very confused about what’s going when it ends..

Do we really have to  strike our hands together violently to indicate appreciation for what somebody did?

In a recent article in Esquire, Elwyn Simons, head of Duke University’s Division of Fossil Primates, says “We don’t know know how far back it goes… but you don’t find primates doing it unless they’ve been taught to do it. They do not clap hands in the wild. It’s not to applaud something. It’s because they’re frightened or want to call attention to food”.

Their might be hundreds alternatives to clapping, so the question remains.. Why do we clap?