Nearly a quarter of the world's land mammal species are at risk of extinction, and many others may vanish before they are even known to science, according to a major annual survey of global wildlife.

一项对全球野生动物的大规模年度调查表明，近四分之一的陆地哺乳动物物种濒临灭绝，还有许多其余的物种，甚至在科学界知道它们之前可能就已经绝迹了。

youdao

The whales travel about 50 to 90 miles a day, says Alex Zerbini at the National Marine Mammal Laboratory, Alaska Fisheries Science Center in Seattle.

西雅图阿拉斯加渔业科学中心的国家哺乳动物实验室的Alex Zerbini告诉我们，这些鲸鱼一天内可以游50至90英里。

youdao

The first results are published in the journal Marine Mammal Science.

BBC: Seal pup

She said the animal science building would include aquatic, reptile and mammal rooms, a laboratory and six teaching classrooms.

BBC: Dorset colleges receive government renovation grants

The prospect of cloning a human moved from science fiction into the realm of possibility in 1997, when Dolly the sheep became the first mammal to be cloned from an adult.

CNN: Group says it will move human cloning work offshore