title: Involvement of circadian clock in crowing of red jungle fowls (Gallus gallus).
abstract: The rhythmic locomotor behavior of flies and mice provides a phenotype for the identification of clock genes, and the underlying molecular mechanism is well studied. However, interestingly, when examining locomotor rhythm in the wild, several key laboratory-based assumptions on circadian behavior are not supported in natural conditions. The rooster crowing 'cock-a-doodle-doo' is a symbol of the break of dawn in many countries. Previously, we used domestic inbred roosters and showed that the timing of roosters' crowing is regulated by the circadian clock under laboratory conditions. However, it is still unknown whether the regulation of crowing by circadian clock is observed under natural conditions. Therefore, here we used red jungle fowls and first confirmed that similar crowing rhythms with domesticated chickens are observed in red jungle fowls under the laboratory conditions. Red jungle fowls show predawn crowing before light onset under 12:12 light : dim light conditions and the free-running rhythm of crowing under total dim light conditions. We next examined the crowing rhythms under semi-wild conditions. Although the crowing of red jungle fowls changed seasonally under semi-wild conditions, predawn crowing was observed before sunrise in all seasons. This evidence suggests that seasonally changed crowing of red jungle fowls is under the control of a circadian clock.
authors.affiliation: School of Agriculture, Tokai University, Aso, Kumamoto, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Ito
authors.affiliation: Graduate School of Agriculture, Tokai University, Aso, Kumamoto, Japan.
authors.forename: Shuho
authors.initials: S
authors.lastname: Hori
authors.affiliation: School of Agriculture, Tokai University, Aso, Kumamoto, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Hirose
authors.affiliation: Graduate School of Agriculture, Tokai University, Aso, Kumamoto, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Iwahara
authors.affiliation: Graduate School of Agriculture, Tokai University, Aso, Kumamoto, Japan.
authors.forename: Azusa
authors.initials: A
authors.lastname: Yatsushiro
authors.affiliation: Kumamoto City Zoological and Botanical Gardens, Kumamoto, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Matsumoto
authors.affiliation: Kyoto City Zoo, Kyoto, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: School of Agriculture, Tokai University, Aso, Kumamoto, Japan.
authors.forename: Chinobu
authors.initials: C
authors.lastname: Okamoto
authors.affiliation: National Institute of Agribiological Sciences, Tsukuba, Japan.
authors.forename: Ken-Ichi
authors.initials: KI
authors.lastname: Yayou
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.|Division of Seasonal Biology, National Institute for Basic Biology, Okazaki, Aichi, Japan.|Department of Basic Biology, The Graduate University for Advanced Studies (SOKENDAI), Miura, Kanagawa, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Shimmura
mesh_terms: D000818:Animals; D000830:Animals, Laboratory; D001522:Behavior, Animal / Q000502:physiology*; D002645:Chickens / Q000502:physiology*; D057906:Circadian Clocks / Q000502:physiology*; D008027:Light; D008297:Male; D012621:Seasons; D014828:Vocalization, Animal / Q000502:physiology*
keywords: circadian clock; crowing; red jungle fowl; season