Cataglyphis ants of the Sahara Desert are extremely aggressive toward members of other colonies if they are close to their nest entrance, but not once they have embarked on their wide foraging journeys. We show that the ants reach the same level of aggressiveness when they are far from their actual nesting site but their path integrator--their main navigational toolkit--tells them that they are close, indicating a role for the animal's path integrator beyond navigation.