大白鯊的GPS是什么？

Sharks use the Earth’s magnetic field as a sort of natural GPS to navigate journeys that take them great distances across the world’s oceans, scientists have found.

科學(xué)家發(fā)現(xiàn)，鯊魚(yú)可以利用地球磁場(chǎng)作為一種天然的全球定位系統(tǒng)(GPS)來(lái)進(jìn)行穿越世界海洋的長(zhǎng)途旅行。

Researchers said their marine laboratory experiments with a small species of shark confirm long-held speculation that sharks use magnetic fields as aids to navigation — behavior observed in other marine animals such as sea turtles.

研究人員說(shuō)，他們?cè)诤Ｑ髮?shí)驗(yàn)室對(duì)一種小型鯊魚(yú)進(jìn)行的實(shí)驗(yàn)證實(shí)了長(zhǎng)期以來(lái)的猜測(cè)，即鯊魚(yú)利用磁場(chǎng)作為導(dǎo)航輔助手段，同時(shí)在海龜?shù)绕渌Ｑ髣?dòng)物身上也觀察到了這種行為。

Their study, published this month in the journal Current Biology, also sheds light on why sharks are able to traverse seas and find their way back to feed, breed and give birth, said marine policy specialist Bryan Keller, one of the study authors.

這項(xiàng)研究的作者之一、海洋政策專家布賴恩·凱勒表示，他們的研究成果發(fā)表在本月的《當(dāng)代生物學(xué)》雜志上，也揭示了為什么鯊魚(yú)能夠穿越海洋，還能找到回去覓食、繁殖和生產(chǎn)的路。

“We know that sharks can respond to magnetic fields,” Keller said. “We didn’t know that they detected it to use as an aid in navigation ... You have sharks that can travel 20,000 kilometers and end up in the same spot.”

“我們知道鯊魚(yú)能對(duì)磁場(chǎng)做出反應(yīng)，”凱勒說(shuō)，“我們不知道他們是如何來(lái)導(dǎo)航的，無(wú)法想象鯊魚(yú)可以游兩萬(wàn)公里，還能回到最初的起點(diǎn)。”

The question of how sharks travel long distance has long intrigued researchers.

鯊魚(yú)是如何長(zhǎng)途旅行的問(wèn)題一直吸引著研究人員。

Looking for answers, Florida State University scientists decided to study bonnethead sharks — a hammerhead that lives on both American coasts and returns to the same estuaries every year.

為了尋找答案，佛羅里達(dá)州立大學(xué)的科學(xué)家們決定研究大白鯊——一種生活在美國(guó)海岸和每年返回同一河口的錘頭鯊。

Researchers exposed 20 bonnetheads to magnetic conditions that simulated locations hundreds of kilometers away from where they were caught off Florida.

研究人員將20條大魚(yú)暴露在磁場(chǎng)條件下，這些磁場(chǎng)條件模擬了它們?cè)诜鹆_里達(dá)州附近數(shù)百公里外被捕獲的地點(diǎn)。

They found that the sharks began to swim north when the magnetic cues made them think they were south of where they should be.

他們發(fā)現(xiàn)，當(dāng)磁信號(hào)讓鯊魚(yú)以為自己在的南方時(shí)，它們開(kāi)始向北游去。

That finding is compelling, said Robert Hueter, senior scientist emeritus at Mote Marine Laboratory & Aquarium, who was not involved in the study. Hueter said further study is needed to find how the sharks use the magnetic fields to determine their location and whether larger, long-distance migrating sharks use a similar system to find their way.

莫特海洋實(shí)驗(yàn)室和水族館的退休高級(jí)科學(xué)家羅伯特·休特(Robert Hueter)說(shuō)，這一發(fā)現(xiàn)令人信服，他沒(méi)有參與這項(xiàng)研究。休特說(shuō)，還需要進(jìn)一步的研究來(lái)發(fā)現(xiàn)鯊魚(yú)是如何利用磁場(chǎng)來(lái)確定自己的位置的，以及大型、遠(yuǎn)距離遷徙的鯊魚(yú)是否使用類似的系統(tǒng)來(lái)確認(rèn)方向。