Top Rooster in Pecking Order Crows First in the Morning

Posted on July 27, 2015

Roosters in the morning

Scientists from Nagoya University have determined that roosters crow in descending order of their pecking order ranking. The top ranking rooster crows first in the morning, starting off the day with the distinct "cock-a-doodle-do" sound. He is followed in sequence by the second highest ranking rooster and then the third highest ranking rooster and on down the group in order of rank.

The study by Tsuyoshi Shimmura, Shosei Ohashi & Takashi Yoshimura from the Institute of Transformative Bio-Molecules (ITbM) at Nagoya University is based on the study of different groups of roosters. The researchers say crowing is an action by roosters to alert other of their territory. When the top rooster crows other roosters nearby also start to crow like a ripple effect.

The scientists also found that the starting time for the first morning crow from the top rooster varied from day to day. However, the crowing of lower ranking roosters always starts right after the crowing of the top ranking rooster. If the top ranking rooster was removed from the group then it would be the second highest ranking rooster in the pecking order that gave the first morning crow.

Yoshimura, the leader of the research study, says in a statement, "We have discovered that roosters live in a strictly linear hierarchy, where social ranking reflects the order to announce the break of dawn."

A research paper on the crowing order of roosters was published here in the journal, Scientific Reports.

Photo: Tsuyoshi Shimmura and Tomo Nakamura; ITbM, Nagoya University