![解释公鸡打鸣（图）]( "解释公鸡打鸣（图）")
'Cock-a-Doodle-Doo!' on Cue
by Emily
Underwood 胡德良 译
| Although the rooster's strident wake-up call just before
sunrise feels as regular as an alarm clock, the evidence that the
birds are somehow driven to herald the dawn has long been
anecdotal. After all, a rooster is rarely shy about making his
presence known regardless of the time of day. Now, Japanese
scientists have quite literally shed light on the phenomenon. To
see whether roosters simply crow in response to external stimuli or
according to a circadian rhythm—an internally driven, cyclical
pattern of behavior that occurs over a 24-hour period—the team put
one group of birds into a room with continuously dim lights and
tracked the birds' crowing over the course of a month. Even in the
absence of a daily cycle of light and dark, the authors report
today in Current
Biology, the
roosters continued to crow near dawn, suggesting that the birds' cacophonous racket is indeed
controlled by an internal circadian clock. However, over time their
crows became more scattered, suggesting that the rhythm eventually
faded as they adjusted to a new regime of perpetual
twilight. |
尽管公鸡在黎明前刺耳的打鸣就像闹钟一样有规律，但是一直以来，这种鸟类预示黎明的机制在某种程度上仍不确定。毕竟，公鸡并不会因为白天的到来而羞于表现自己。目前，日本的科学家们如实地解释了这个现象。为了搞清公鸡是外部刺激还是由于昼夜生理节奏而导致打鸣的，研究小组将一群公鸡关在一个光线一直暗淡的房间里，在一个月的时间里记录公鸡的鸣叫。如果是内部因素驱使的话，那么就会遵循24小时鸣叫一次的模式。今天，研究论文的作者们在《当代生物学》杂志上报道说：即使在没有昼夜分明的光线条件下，这些公鸡仍然会在黎明前后鸣叫，这表明确实有一个内部的昼夜时钟控制着公鸡刺耳的鸣叫。然而，随着时间的推移，这些公鸡的鸣叫变得更加散乱了，说明由于处于陌生而长期的黎明环境中，最终会逐渐致使鸣叫的节奏消失掉。 |
译自：美国《科学》杂志网站（18 March 2013, 12:00 PM）
原著：Emily Underwood
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青春就应该这样绽放 游戏测试：三国时期谁是你最好的兄弟！！ 你不得不信的星座秘密