The crow of a rooster at sunrise is one of the most well-known phenomena on earth. To some it can be charming, but for others it can be frustrating to lose those extra hours of sleep. However, while we all know that roosters crow in the morning, why, exactly, do they do so? Turns out, there’s more than one answer to this question:
Oddly enough, it wasn’t until 2013 that we finally got to the bottom of why roosters crow at sunrise, and the answers were surprising. It turns out, roosters don’t actually crow right at sunrise, but a few hours before. That’s because they have a mean internal circadian rhythm clock of 23.8 hours, thus making them crow at the appointed time.
Announcing their territory
We know what sets roosters off (their circadian rhythm), but why is it so important for them to start crowing in the morning? While it isn’t fully understood, a leading theory is that they’re announcing their territory. Many chickens find their roots in countries such as Myanmar, Thailand, India, and China where they would live in dense, jungle areas. In these areas, it would be difficult to see other chickens, and thus crowing was a way to announce their presence and to declare that the area they were in was their territory. In modern times, then, waking up in the morning and crowing is a way for roosters to re-announce their presence and authority.