手机APP下载

您现在的位置: 首页 > 在线广播 > 科学美国人 > 科学美国人地球系列 > 正文

科学美国人60秒:年轻大白鲨吃底栖鱼类

来源:可可英语 编辑:aimee   可可英语APP下载 |  可可官方微信:ikekenet
  


扫描二维码可进行跟读训练
  下载MP3到电脑  [F8键暂停/播放]   批量下载MP3到手机
5cD+X;I4aD

)W|QK^b.2O]

This is Scientific American's 60-second Science, I'm JasonGoldman.
The image of a dorsal fin cutting through the sea surface is iconic. But scientists studying the stomach contents of young great white sharks off the coast of Australia were in for a surprise when they learned that the predators seem to spend a lot of time patrolling the seafloor.
"They have a predominantly fish-based diet, which is not unexpected for juvenile white sharks. The most important prey species we identified was eastern Australian salmon."
University of Sydney graduate student Richard Grainger. He and his team sorted through the stomach contents of more than 50 juvenile white sharks that died after being entangled in shark exclusion nets meant to protect swimmers.
"The overall unexpected finding was just the diversity and importance of bottom-dwelling fishes. Things like stargazers—which bury themselves in the sand, they're quite strange-looking fish—and flathead but also stingrays."

bzTrN2ZYSpSE

大白鲨.jpg
People actually did not have a good idea of the particulars of great white shark diets. As Grainger points out, the sharks enjoy protections throughout the world. So most researchers estimated their diets through the chemical markers that they can ethically access by taking small skin samples. These measurements indicate at what level of the food chain the predator is feeding but not the actual critters that make up their meals.
"There's quite a lot of evidence that lots of different animals, so even carnivores, omnivores, herbivores self-select different prey or food based on a particular balance of nutrients."
Grainger hopes that by further understanding what juvenile white sharks like to eat, he can begin to piece together how and why they make their predatory choices. The study was published in the journal Frontiers in Marine Science.
"Understanding and predicting when sharks might be more abundant in certain areas would be an ultimate end goal."
Avoiding or mitigating human-shark conflicts means understanding the sharks' nutritional goals. And if researchers can anticipate where and when sharks are likely to spend their time hunting, they can better protect humans from getting bitten—and sharks from getting killed.
Thanks for listening for Scientific American's 60-second Science. I'm Jason Goldman.

KjMatZ17WQR

@QIxI#I,D)LEOpc

jGIyfdsybQK-&^]YAKa,R7I[STkxTr0q,R9PgFe!JKSik+P+k

重点单词   查看全部解释    
predator ['predətə]

想一想再看

n. 食肉动物,掠夺者

联想记忆
determine [di'tə:min]

想一想再看

v. 决定,决心,确定,测定

联想记忆
identified

想一想再看

adj. 被识别的;经鉴定的;被认同者 v. 鉴定(id

 
prey [prei]

想一想再看

n. 被掠食者,牺牲者
vi. 捕食,掠夺,使

 
ultimate ['ʌltimit]

想一想再看

n. 终极,根本,精华
adj. 终极的,根本

 
exclusion [iks'klu:ʒən]

想一想再看

n. 排除,除外,逐出

 
unexpected ['ʌnik'spektid]

想一想再看

adj. 想不到的,意外的

 
indicate ['indikeit]

想一想再看

v. 显示,象征,指示
v. 指明,表明

联想记忆
sheer [ʃiə]

想一想再看

adj. 纯粹的,全然的,陡峭的
adv. 完

 
diversity [dai'və:siti]

想一想再看

n. 差异,多样性,分集

联想记忆

发布评论我来说2句

    最新文章

    可可英语官方微信(微信号:ikekenet)

    每天向大家推送短小精悍的英语学习资料.

    添加方式1.扫描上方可可官方微信二维码。
    添加方式2.搜索微信号ikekenet添加即可。