有的鯊魚(yú)也是吃素的

目前，科學(xué)家們確定了第一個(gè)不只吃肉的鯊魚(yú)物種。

The bonnethead shark, a smaller relative of the hammerhead, has been found to digest vast amounts of seagrass as well as meat.

窄頭雙髻鯊(bonnethead shark)是槌頭雙髻鯊(hammerhead shark)的小型親戚，如今已被確認(rèn)能夠像消化肉類般消化大量海草。

The shark was long thought to be a strict carnivore that occasionally ingested greens by accident, passing them through the gut without processing them properly.

長(zhǎng)期以來(lái)，鯊魚(yú)一直被嚴(yán)格歸類為肉食性動(dòng)物。即使它們偶爾誤食一些植物，這些植物在通過(guò)腸道時(shí)也不會(huì)被消化。

But in tests they proved better at digesting vegetable matter than a panda and almost as good as sea turtles, suggesting plants are a key part of their diet.

但現(xiàn)在有試驗(yàn)證明，它們消化植物的能力比熊貓還強(qiáng)，幾乎與海龜一樣厲害，這表明植物也是它們的關(guān)鍵飲食組成。

Sharks had previously been 'uniformly accepted as carnivores', according to the researchers from the University of California, Irvine.

加州大學(xué)歐文分校的研究人員表示，鯊魚(yú)以前「被一致視為肉食性動(dòng)物」。

They found, however, that seagrass can form up to 62 per cent of the bonnethead diet, alongside their preferred meal of crustaceans and molluscs.

然而，他們現(xiàn)在發(fā)現(xiàn)，在窄頭雙髻鯊的飲食習(xí)慣中，海草占到了高達(dá)62%的比例。其次才是它們愛(ài)吃的甲殼類動(dòng)物和軟體動(dòng)物。

Although researchers have long known that the tiny species eats copious quantities of seagrass, it was not believed to absorb any nutrients from it.

雖然研究人員早就知道這種小型物種會(huì)吃掉大量的海草，但卻認(rèn)為它們不會(huì)從中吸收任何營(yíng)養(yǎng)成分。

'Until now, most people thought that seagrass consumption was incidental when these sharks were hunting for crabs that live in the seagrass beds,' said study co-author Samantha Leigh.

該研究共同作者Samantha Leigh表示：「至今為止，大多數(shù)人都認(rèn)為它們只是在海草床上尋找螃蟹時(shí)偶然誤食海草」。

Over the course of three weeks, the team conducted a series of lab-based trials in which they fed bonnethead sharks a diet of 90 per cent seagrass and 10 per cent squid.

在三個(gè)星期內(nèi)，該團(tuán)隊(duì)進(jìn)行了一系列基于實(shí)驗(yàn)室的試驗(yàn)。在這些試驗(yàn)中，他們給窄頭雙髻鯊喂食了90%的海草與10%的魷魚(yú)。

They then analysed how much of the nutrients the animals digested, and how much they excreted.

隨后，他們?cè)俜治鲞@些動(dòng)物消化了多少營(yíng)養(yǎng)素，以及排出了多少。

Not all carnivores can digest plant material efficiently, but sharks fed the seagrass-heavy diet all gained weight, the team found.

研究團(tuán)隊(duì)發(fā)現(xiàn)，并非所有肉食性動(dòng)物都能有效地消化植物，但大量喂食海草后的鯊魚(yú)都增重了。

The animals were found to be as good at digesting fibre and organic matter as young green sea turtles - a species that transforms from eating an omnivorous diet in youth to committed vegetarianism in adulthood.

他們還發(fā)現(xiàn)，這種動(dòng)物對(duì)于纖維與有機(jī)物的消化能力堪比年輕的綠海龜(綠海龜年輕時(shí)為雜食性動(dòng)物，成年后則變?yōu)樗厥硠?dòng)物)。

'Bonnethead sharks are not only consuming copious amount of seagrass but they are actually capable of digesting and assimilating seagrass nutrients, making them clear omnivores,' the researchers wrote in the journal Proceedings of the Royal Society B.

研究人員在《Proceedings of the Royal Society B》期刊上寫(xiě)道：「窄頭雙髻鯊不僅會(huì)食用大量海草，而且它們實(shí)際上還能夠消化與吸收海草中的營(yíng)養(yǎng)素，這就令其明顯成為了雜食性動(dòng)物」。

Averaging 30-48 inches (76-120cm) in length and weighing up to 11 kilograms (24lb), bonnetheads are found on the Atlantic and Gulf of Mexico coasts of the US.

據(jù)悉，窄頭雙髻鯊平均長(zhǎng)度為76-120厘米，重達(dá)11千克左右，且在大西洋與美國(guó)的墨西哥灣海岸均有出沒(méi)。