The picture says it all. I've had all these good things to write about come up, and then BOOM this new grant socked me right in the bean machine and my life instantly shattered into little pieces of madness. In short, I have too much stuff to do, and my hands are sore from all the writing.
In truth, the submissive behavior this (zoo) baboon appears to begin by presenting his butt, a standard submissive behavior, but then everything shifts into nightmare world territory when he lifts the leg, starts screaming at the humans, and does the weird hand thing. I've seen the hand thing before, but in macaque monkeys. And its only this one guy in the colony who will sometimes rest his hand near his tail when he is being groomed from behind. He's a bit of a jittery monkey overall, but not totally neurotic; he's much calmer than that baboon is under similar circumstances.
Then again, its also a juvenile, so his behavior is difficult to analyze. There must be something ethologically relevant to "hand-to-butt" behavior, though. I've seen it too many times in too many species. Its related to the presentation behavior, which is in turn derived from the female copulation stance. Females don't have the luxury of being able to scratch their butts during copulation; there's an awful lot of force involved, and the female's frame needs all the support it can get to absorb it all. Where would the added hand gesture have originated? Oh look, I found at least one recent, directly relevant article discussing this subject.
Well look at that, complex thought is still possible in my mind afterall. I'm too curious not to write up a synopsis of these findings regarding the copulation position, and I do have a much needed vacation coming up.