Bees calculate how much energy they need to get pollen. To survive, bees must run on a "profit" basis. They must not use more energy in obtaining nectar than energy the nectar provides. Bees were given the choice of travelling along two pathways to get nectar. One pathway was 10 meters long, the other 20 meters. However, the "scenery" of the 10 meter pathway was designed to trick the bees into perceiving that it was the furthest distance away. When the bees returned to their fellows in the nest they told them with a waggle dance which pathway to use to get more pollen. Despite the 10 meter pathway appearing to the bees to be further away they told other bees to go to the feeder in the 10 meter pathway. Somehow, they had worked out that it used up less energy to go to this feeder than the one on the other pathway. It is believed that bees have "calorimeters" built into their brains. They do not judge energy expenditure solely based on distance travelled...