Apparently the choice trivia is found .... Why rooster sings every morning?

Apparently the choice trivia is found ....   Why rooster sings every morning?

No one knows exactly why crows he says songs since dawn. This was the object of study at the University of Nagoya, Japan, who advanced to a genuine experiment to discover the secrets of awakening early morning rooster.
Thus, they can find answers on the questions: How do you know that dawn is approaching crows? I know it from twilight, or knows very well the clock?

So the scientists decided on a turkey room where the lights were weak for 24 hours. All turkeys and "kikirikuuuu" they leave were recorded for a month, with special and specific equipment.
Finally, analysis of the data collected showed that even when there are no external influences that show the arrival of dawn, turkeys continued in the same manner before dawn as before.

The conclusion is that peanut-t obey the so-called circadian rhythm, a cycle of 24 hours that dictates the biological clock in the brain to synchronize physiological functions in the day-night cycle, writes Living. But over the course of days, there was a small disturbance, very easy for turkeys, an indicator that the biological clock is also based on external factors to keep pace appropriate