Later the scientists took the honeybees to New York. The bees came for the food at the time their bodies told them, only it was 3:00 p.m. New York time. Their bodies were still on Paris time.
Humansm like other animals, have a biological clock that tells us when to sleep and eat. It causes other changes too. Blood pressure is lower at night, the heartbeat is slower, and the body temperature is a little lower. We even go through several levels of sleep, cycles of deep and light sleep.
Other events occur in cycles too. More babies are born between midnight and dawn than at any other time. More natural deaths occur at night, but more heart attacks happen early in the morning.
Most deaths from diseases in hospitals occur between midnight and 6:00 a.m. Some police sey there are more violent crimes and traffic accidents when there is a full moon.
The honeybees in the experiment reset their biological clock for different feeding hours. Humans do this too. People who work at night learn to sleep during the day eat at night. Students who fly halfway across the world to study in another country get used to the new time zone after a few days. When day go home, they change back again. Our bodies are controlled by a biological clock, but we can learn to reset it to a different time.