The whole bunny-ears thing

The kid to the far right (I'm not sure of his name) tried desperately to get behind kids and do the whole "bunny ears" thing while I was taking the picture. He was late on all the pics except this one. It made his day.

I think back to when I was a kid. I did the same thing. What is the significance of the whole rabbit-ear deal? Who thought of this hand motion? Somehow it has been passed down from generation to generation. Are parents actually teaching kids this? I'm trying to remember how I picked it up. I'm not coming up with anything. Maybe it's some genetic brain twitch that is triggered by the appearance of a camera. Seriously, does anyone ever recall being told that this was a cool thing to do? It must just happen naturally. Most children find this to be tremendously hilarious, breaking forth into howls of great mirth. A similar reaction can be found in their response to knock-knock jokes. Is it really worth snorting chocolate milk over? Apparently so.