The Swarm Within How Ant Colonies Think Without a Leader

There is one job that no ant has. It exists in nearly every human institution, from corner shops to armies to governments, and it is missing from a colony of a million insects. That job is manager. No ant reports to a supervisor, and no ant hands out assignments. Nobody holds a plan for the whole colony, and nobody is even aware that a whole exists.

This sounds wrong, because the evidence in front of us looks so organized. Ant colonies harvest seeds, rear young, defend territory, and in some species grow crops and keep livestock. Colonies of one species build bridges out of their own bodies. Work on that scale seems to demand a planner, and most of us have long carried one in our mental picture: the queen. We imagine her on a throne deep in the nest, issuing decrees to the workers.

The biology says otherwise. The queen is an egg layer. That is her function, and it is a vital one, but it is not command. She does not survey the colony, weigh its needs, and send orders. The myth of the ant queen persists, as one Scientific American account of the research puts it, because it resonates with the hierarchical way many human organizations work, and it gives us a convenient picture of how complex behavior could be organized. We took our own org chart and projected it onto the insects.

What actually happens is stranger and more interesting. The colony is made up of individual ants, each acting on its own local sensing and its own primitive decision making. Each responds to nearby signals. Each is caught up in feedback loops, where what one ant does changes what the next ant senses. From all that small, local, uncoordinated activity, something that looks like intelligence rises to the level of the group.