Ants leave trails of pheromones when they walk as maps for other ants to follow, meaning they can travel the fastest route to sources of food or to their hive. The more ants that walk that route, the stronger the map is for others to follow, so even if a few ants get temporarily lost they will generally find their way back home. The amazing thing is that the ants don’t smell the pheromones, but detect them with their antennae!