音頻科普:窄頭雙髻鯊是水下割草機
The hammerhead relatives consume copious amounts of sea grass, and have the digestive machinery to process it—making them true omnivores. Christopher Intagliata reports.錘頭鯊的親戚消耗大量的海草,並且有消化機製來消化——這使它們成為真正的雜食動物。克裏斯托弗·因塔利亞塔報道。
撰文\播音:克裏斯托弗·因塔利亞塔(Christopher Intagliata)
翻譯:邱燕寧
審校:郭曉
. Or even omnivores. But about 10 years ago, scientists documented a dainty relative of the hammerhead shark, , consuming copious amounts of sea grass.
鯊魚通常不被認為是素食主義者或者雜食動物。但大約10年前,科學家記錄了錘頭鯊的一種小巧的近親,名叫窄頭雙髻鯊,它們消耗了大量的海草。
"A lot of people kind of just thought they were consuming it incidentally, after going after crabs and squid and other little invertebrates that live in the sea grass meadows." Samantha Leigh, a PhD candidate at the University of California, Irvine. "So everyone thought they were kind of just passing it through their system and not really getting anything from it."
“很多人都隻是認為,它們在追趕螃蟹、烏賊和其他生活在海草場中的小型無脊椎動物時,順便吃了海草。”加州大學爾灣分校博士生Samantha Leigh如是說。“所以每個人都認為海草隻是通過了它們的消化係統,鯊魚並沒有從中得到任何東西。”
So Leigh and her colleagues hauled five of the small sharks back to a Florida lab, and put them on a three-week diet: 90 percent sea grass, 10 percent squid. And analyzed the digestibility of that diet. Turns out, the sharks actually put on pounds, and were able to digest the sea grass just as well as young green sea turtles do.
於是,Leigh和她的同事們把5條小鯊魚帶回了佛羅裏達的實驗室,讓它們進行三周的特殊飲食計劃:90%的海草,10%的烏賊。之後他們分析了鯊魚對這些食物的消化率。事實證明,鯊魚的體重的確增加了,它們能像年輕的綠海龜一樣消化海草。
"It seems like even though the bonnethead shark has what scientists would deem a carnivorous gut, they are definitely acting like omnivores. So there's probably something going on, on probably a microbial level, that's helping them break down this sea grass."
The full nutrition info is in the Proceedings of the Royal Society B. [Samantha C. Leigh et al., ]
“看起來,盡管窄頭雙髻鯊擁有科學家認為的食肉腸道,但它們的行為確實像雜食動物。”所以可能有某種東西,比如在微生物水平上,幫助它們分解海草。
完整的營養信息刊登在《英國皇家學會學報B》(Proceedings of the Royal Society B)上。
The study also gives coastal ecosystem managers something new to chew on: these sharks are like lawn mowers, trimming the sea grass, digesting it, and, yes, recycling it. "So they likely play more of a stabilizing role in food web dynamics. They're not a top apex predator. And they're probably playing a large role in nutrient transport in those sea grass meadow ecosystems as well."
這項研究也給了海岸生態係統管理者一些新的東西去研究:這些鯊魚就像割草機,修剪海草,消化並循環利用它們。“因此,它們在食物網動態中扮演的角色更更像是個穩定者。它們不是頂級掠食者。它們可能在這些海草草甸生態係統的營養運輸中也扮演著重要的角色。”
As for whether we might convince more sharks to have a side salad with dinner? "I don't know that we'll be able to do that anytime soon."
至於我們是否可以讓更多的鯊魚在晚餐時吃些沙拉。“我不知道我們是否很快就能做到。”
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