Video documentary

Ants foraging for food: I also use this as example of how a model can help develop theories. One story (which I am sure is not scientifically accurate, but serves the purpose) is that the simulation was set up and run but found that even after the food source was depleted, in the simulation the ants still continued to return to the site of the food source whereas in real life, once the source had been depleted, the ants moved on. So clearly there was something missing from the simulator - and this lead to a possible theory that the ants secrete a hormone/chemical on the path back to the 'nest' (or some chemical) that indicates/communicates to the other ants that that particular food is finished.