Life in the Undergrowth: Ant Tracks

Ants communicate by leaving trails of chemicals that other ants can follow to sources of food they've found. Very quickly after a new source of food is found ants from the nest are following the shortest path to get to it, even if the original ant trail was not that direct and wiggled around. How do they do that?

Bongo playing physicist, Richard Feynman, better known for his Nobel Prize for Physics, wondered about this one day watching ants in his bath. The marvellous thing about science is it can be done anywhere! He grabbed some crayons and started marking the paths each ant followed by drawing a line behind it. He quickly discovered from the trails that what was happening was that each ant was following earlier trails but hurriedly so not sticking to it exactly. Instead it was leaving its own trail. As this was done over and over again the smooth direct route emerged as having the strongest line from the superimposed hurried trails. It's a bit like when you sketch - you do a series of rough lines to start, but as you do that over and over the final line is much smoother.

From very simple behaviour the ants are able to achieve complex things that might otherwise need complex geometrical skills. Computer Scientists have been inspired by the ants when designing software and have come up with the idea of 'ant algorithms' - ways of programming separate software agents to do complex things that otherwise would bog down even fast computers. Finding shortest routes, for example for taxi drivers or for messages sent over networks, is a very common problem of this kind. An Ant algorithm solution involves programming lots of software agents to behave like ants leaving digital trails for other agents to pick up.

So ants are helping to solve real problems for real companies. Not bad for such a tiny brain.