時差N小時:擾人的雄雞打鳴(下) Disturbing rooster

Most people assume that roosters are programmedto crow at the first sign of sunlight to announce thedawning of a new day, or some such romanticnotion.

大多數(shù)人都會認(rèn)為每當(dāng)?shù)谝豢|陽光照耀大地，公雞就會按規(guī)律打鳴表示嶄新一天的開始。除此之外還有很多關(guān)于此浪漫的傳說。

Like all birds, roosters call in a daily cycledetermined by circadian rhythms.

和其他鳥類一樣，公雞每天打鳴的習(xí)慣是由生理節(jié)律所決定。

That is, a rooster's internal clock allows it toanticipate the sunrise and prepare for another exciting day of looking for food.

公雞的生物鐘讓它期待日出，以此為契機(jī)開始新一天的覓食。But why must roosters crow as theyprepare to start their day, and why do some roosters sound off before dawn?

但是，為什么公雞會打鳴，而且這一時間點(diǎn)是在黎明前呢?

Roosters are territorial creatures and don't much like other roosters trespassing on their land.

公雞是具有領(lǐng)地意識的動物，決不許其它公雞侵犯自己的領(lǐng)地。

They crow in order to establish their domain and warn other roosters to stay away or prepare tobrawl.

為了守護(hù)自己的地盤，警告其它公雞遠(yuǎn)離進(jìn)而避免爭斗。

And because their internal clocks are sometimes set a bit early, some roosters begin crowingwell before sunrise.

而且公雞的生物鐘有時候設(shè)置得早一些，所以有些公雞是在日出前打鳴。