Have you ever noticed an ant in your home, only to find that a week later the whole colony has moved in? The traps you set up catch only a few of these ants, but soon, the rest of the colony has mysteriously disappeared. Now, a study published in the journal Cell on June 14 explores how certain danger-signaling pheromones—the scent markers ants emit to communicate with each other—activate a specific part of the ants' brains and can change the behavior of an entire nest.