The rooster's crow or the rising sun?
Genes, Not Light, Make Roosters Crow at Dawn : Discovery News
"To solve the mystery, Yoshimura and colleagues kept roosters under round-the-clock dim lighting. This didn’t deter the roosters. No matter what, they kept crowing each morning just before dawn. The researchers say this is proof that the vocalizing is entrained to a circadian rhythm. In short, the roosters are genetically programmed to crow at a certain time. At some point, the rising sun set the roosters’ internal clock, so now they crow every 24 hours."
I often wondered why i would hear roosters crowing as early as 4 or 5 in the morning when the sun had not even risen yet!
Genes, Not Light, Make Roosters Crow at Dawn : Discovery News
"To solve the mystery, Yoshimura and colleagues kept roosters under round-the-clock dim lighting. This didn’t deter the roosters. No matter what, they kept crowing each morning just before dawn. The researchers say this is proof that the vocalizing is entrained to a circadian rhythm. In short, the roosters are genetically programmed to crow at a certain time. At some point, the rising sun set the roosters’ internal clock, so now they crow every 24 hours."
I often wondered why i would hear roosters crowing as early as 4 or 5 in the morning when the sun had not even risen yet!