海豚媽媽母愛博大 有換子而養的現象(上)

Recognising a mother's call is one of theearliest and most important life lessons for a dolphin calf.

對小海豚而言，辨別母親的呼喚是它們最早、也是最爲重要的功課。

They can easily be separated from theirmothers in the vast open ocean, so listening out for her call means they couldquickly reunite.

在浩瀚的大海中，它們很容易就會和母親分離，因此，留心傾聽母親的呼喚意味着它們能很快再次會合。

But just how early a calf learns itsmother's call was not fully understood. In a new study of bottlenose dolphins,researchers listened in on two captive dolphin mothers to understand howmother-calf recognition develops.

但是，小海豚到底多大就能學會聽母親的呼喚，我們還不十分清楚。在一項對寬吻海豚（bottlenose dolphin）的最新研究中，研究人員對兩位圈養的海豚媽媽進行監聽，試圖瞭解海豚媽媽和小海豚之間的辨識是怎樣建立的。

They discovered that the mothers rapidlyincrease their unique "signature whistles" as soon as the calf isborn. They whistle up to five times more than usual. But they also saw themothers do something completely unexpected.

他們發現，小海豚剛一降生，海豚媽媽很快就能發出獨特的“唿哨信號”。她們發出的唿哨要比平時多出五倍，但是，研究人員也發現了海豚媽媽一些完全出乎他們意料的做法。

We were surprised at how strong the resultswere, says Stephanie King of the University of Western Australia, who led theresearch at the Dolphin Research Center, a sea pen facility in Florida, US.

西澳大利亞大學研究人員斯蒂芬妮·金（Stephanie King）負責領導海豚研究中心的這項研究。該中心是設在美國佛羅里達州的一個海筆（sea pen）研究設施。她表示，“我們對研究結果頗感意外。

We call this 'vocal imprinting', where thecalf imprints on its mother’s signature whistle, says King.

斯蒂芬妮·金表示，“我們將小海豚要學會的媽媽唿哨信號中的印記稱爲‘聲音印記’。”

It's an important learning phase where thecalf learns to recognise its mother, and it's important this happens quicklybefore mother-calf separations occur.

“小海豚學習辨別自己的媽媽是個重要的學習階段，在和海豚媽媽分離前，小海豚就進入這個階段非常重要。”

It was already known that it takes a calfseveral months to develop its own unique call. "They are not born with asignature whistle, they learn it," says King.

目前已經得知，小海豚要花好幾個月時間才能學會發出自己獨特的呼喚。斯蒂芬妮·金表示，“海豚並非生來就會發出唿哨信號，而是後天學會的”。

Until they do so, they have to listenclosely to find their mothers.

在學會發出唿哨信號前，它們不得不仔細聽媽媽的唿哨聲才能找到媽媽。

This work, published in the journal MarineMammal Science, reveals once again how vital sound is to a dolphin's world.

該項目的研究成果發表在《海洋哺乳動物科學》雜誌上，這再次揭示了聲音在海豚世界的重要性。

Two weeks after the calves were born asurprising turn of events took place.

海豚媽媽偷竊其他小海豚的情況十分罕見。

It is rare for a female dolphin to stealanother's calf

小海豚出生兩週後，一件令人意外的事情發生了。