Even more interesting, If staying bipedal means 'lets make sex' for bonobos, I wonder if human observers could change the behaviour of studied bonobos increasing the sexual encounters (just because we are standing there shouting 'lets make sex' with our bodies all the time). Wouldn't be crazy if we repeat the research with robots and remote cameras to find that they are not so promiscuous as we thought?

We must be a particularly foul-mouthed species for them. And we share also the 'stop what you were doing' grab/slap.