This is very very cool. A little gruesome of you are not used to this sort of thing.
I wonder if it had ant insurance.
More like this
I'm actually finding it remarkably easy to answer this question.
I don't often point people to online game-like interactive thingies, but this one has my endorsement. Give yourself a few minutes to watch the process. It can be gruesome:
This is a bit gruesome so I've put it below the fold.
What does an ant do with a femur? I never would have expected them to be interested in bone (or to be able to drag the skull to wherever it is they dragged it). Do some ants have some sort of secretion that could digest bone?
i would guess that they were after the marrow, if they can't break them open they can wait for other microorganisms to break them down a little so they can eat it.
Or maybe they just want a trophy of their victim.
I'm going for trophy explanation .