鲨鱼也吃素？ Indeed!

Tuesday，Jan  09

2018

Sharks are infamous as meat eaters—and human eaters. But now, scientists have discovered the first species to feast on plants.

鲨鱼是出了名的肉食鱼—还有食人鱼。但现在，科学家们发现了第一种吃植物的鲨鱼。

The bonnethead shark (Sphyrna tiburo), which sticks close to shore and hunts in shallow waters frequented by humans, usually dines on shrimp, small crabs, and small fish in seagrass meadows.

窄头双髻鲨生活在岸边水域，经常被人类在浅水区捕获，它通常吃海草区域里的虾，小螃蟹和小鱼。

But in 2007, researchers found something strange in the guts of juvenile bonnethead sharks: the seagrass itself.

但在2007年，研究者们在幼年的窄头双髻鲨的胃里发现了奇怪的东西：竟然是海草本身。

So one adventurous graduate student put several sharks in an outdoor salt-water tank on a diet of 90% eelgrass and 10% squid three times a day for 3 weeks.

于是一个敢于冒险的研究生把几只鲨鱼放在了户外的咸水鱼缸里，在三周的时间内每天三次喂食90%的鳗草和10%的鱿鱼。

Despite this mostly vegetarian fare, all the sharks gained weight, she reported here this week at the Society of Integrative and Comparative Biology annual meeting.

尽管大部分都是素食，所有的鲨鱼都增重了，她在这周举办的综合与比较生物学年会上报告说。

What’s more, carbon tracers in the seagrass—along with an analysis of the sharks’ poop—suggested that they were digesting and using at least half the seagrass they were eating.

另外，对海草的碳元素追踪—还有鲨鱼的排泄物分析—表明，它们所吃的海草至少有一半都被消化且利用了。

But the bonnethead has the same short intestines as its hammerhead relatives, not the longer guts that plant eaters use to digest fibrous material.

但窄头双髻鲨跟它们的亲戚锤头鲨一样小肠都很短，而不像那些食草类动物那样拥有长长的内脏用于消化纤维素材料。

That makes researchers suspect that microbes in the bonnethead shark’s guts are doing the digesting for it.

这让研究者们怀疑窄头双髻鲨内脏里的微生物帮助它进行了消化。

Just don’t expect hammerheads to go green anytime soon.

就不要期待锤头鲨也很快要开始吃素啦！

End

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