Secret Lives of Ants by Jae Choe

Author:Jae Choe
Language: eng
Format: epub, pdf
Publisher: Johns Hopkins University Press
Published: 1999-03-13T16:00:00+00:00

Changes in the Sun’s Position and Internal Clocks

There is a problem with using the sun to navigate. If a long time elapses between the time an ant leaves the nest looking for food and when it goes back to the nest, it will be difficult to use the sun to establish which direction to go in because the sun’s position will have changed considerably. However, in experiments in which scientists found ants that were returning to the nest, caught them, and shut them in a dark box, the ants managed to accurately compensate for the change in the sun’s position and find their way back to their nests. This was possible because a kind of internal clock inside the ants’ brains told them that the hour that had elapsed while they were in the box meant they had to adjust for the fact that the sun’s position had changed by 15 degrees per hour.

This phenomenon has been studied far more thoroughly in honeybees. If a scout bee that left the hive in the morning finds a particularly plentiful source of nectar, when it returns to the nest it will waggle dance for hours to let the other bees know where the source of that nectar is. Even though the bee cannot see the changes in the sun’s position as it dances, every hour it will adjust the direction of the dance by 15 degrees to compensate for the change in the sun’s position. Honeybee brains, too, contain a kind of internal clock.

Compared with ants and bees, human beings do not seem to have such ability to compensate for changes in the sun’s position. We do, however, have a kind of internal clock of our own. People who take transoceanic flights may know in their minds what time it is in their new location, but their bodies stubbornly insist on keeping the same timetable they were on where they came from. Studies of people staying deep underground, with no exposure to the sun, have found that they still tend to live their daily lives on a 24-hour cycle. Strictly speaking, the average human body prefers to go by a 25-hour daily cycle. Were we born by mistake on a planet that revolves an hour too quickly? Perhaps in the ancient past the Earth rotated more slowly than it does now.

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