1. One of the most amazing of living things, the honeybee, has recently been shown to possess still another remarkable skill. It has a built-in alarm clock that goes off exactly every 24 hours.
2. Scientists have long known that bees carry a sort of wrist watch inside their bodies. They will return to the same spot, day after day, right to the minute, to feed on sugar-water left for them. To find out how the bees manage to tell time, an unusual experiment was carried out four years ago. Two young German biologists in Paris trained bees to come out for sugar-water every day at exactly 8:15 p.m. The scientists then set out to baffle the bees. When it is 8:15 p.m. in Paris, New York City's Eastern Day-light Saving time is only 3:15 p.m. If the hive were flown to New York between feedings, which time would the bees follow-Paris’ or New York's?
3. So, immediately after a night feeding in Paris, the hive was sealed and rushed off on an air liner. In New York, scientists from the American Museum of National History placed the hive in a specially prepared laboratory in the museum. At exactly 3:15 p.m. New York time - a precise 24 hours after having been fed in Paris - the bees swarmed out of their hive. The experiment proved conclusively that in spite of a 3,500-mile flight and differences in local time, the bees' alarm clocks rang right on their 24-hour schedule.
4. As further proof, the experiment was repeated-only this time the same hive of bees had its alarm set in New York and was flown to Paris. There, too. They emerged from their hive exactly 24 hours later for their accustomed feeding.
5. Scientists now believe that many, if not all, living things are born with some type of hidden clock. These clocks are sometimes set by the number of hours of light or darkness in a day, by the rhythm of the tides or by the seasons.
6. One of the most remarkable of nature's living clocks belongs to the fiddler crab, that familiar beach-dweller with the overgrown claw. Biologists have long known that the crab's shell is darkest during the day, grows pale in late afternoon, then begins to darken again at daybreak. This daytime darkening is valuable for protection against enemies and sunlight, and for many years it was thought to be a simple response by the crab to the sun-just as if we were to get a tan during the day and lose it at night.
7. But when an enterprising scientist placed a fiddler crab in darkness, he was amazed to find that the color of the crab's shell kept ticking off the time with the same accuracy.