It is a mystery no more: A physical model can explain how a bunch of ants are able, with no visible leader (or highly-developed brains, for that matter) to drag that oversized cake crumb or leaf all the way across your floor to their nest. It turns out that there are, indeed, leaders, of a sort. Those ants you see surrounding the prize being hauled are switching places with other ants that have been scouting out the directions to the nest. The new ants then direct the collective movement, at least for a moment or so until they begin to lose their sense of direction and newer ants take over. The model also solves the second half of the mystery: why the moving crumb never takes the shortest route toward the nest, even though it gets there in the end. Each new ant, in effect, corrects the trajectory of the group.
You can see the experiments here:
Somewhere in this is a message about an efficient kind of group behavior – about the proper balance between conforming and individual initiative, about leaders and followers. Not that humans will be adopting ant methods any time soon (though it does make an interesting thought experiment). But the take-home message may be that sometimes leaders are necessary. We just have to be sure they are the ones holding the knowledge we need in order to get to the right place.