The Scent of Success
Ants don't have eyes that can see long distances, so they navigate using chemistry. When a scout ant finds food, she heads back to the nest while dragging her abdomen along the ground.
This leaves behind a trail of pheromones—invisible chemical 'perfume' that tells every other ant, 'Delicious things this way!'
Building the Highway
An ant trail is a self-reinforcing highway. As more ants follow the initial scent and find food, they add their own pheromones to the path on their return trip.
The more ants that travel the path, the stronger the smell becomes. This turns a faint whisper of a smell into a busy industrial corridor.
Accidental Mathematicians
If there are two paths to food, the ants on the shorter path will return to the nest faster, laying down more pheromones in a shorter amount of time.
Over time, the scent on the shortcut becomes much stronger than the scent on the long, curvy path. Eventually, the long path evaporates and the colony 'locks in' to the straightest line.
Traffic Management
Despite having thousands of ants on a tiny path, they rarely have traffic jams. They use their antennae to sense the pheromone strength and the movement of others.