(单词翻译:单击)
听力文本
Women have a biological cap on their reproductive years.
And from an evolutionary standpoint researchers have long wondered why human female longevity extends well past fertility.
Other than humans, only short-finned pilot whales and killer whales live three or more decades after menopause, some even reaching their 90s.
Male whales, which are far less likely to be followed by group-mates than are females, seldom survive past 50.
Now a study of killer whales offers some clues about why evolution may have selected for such long life:
older females have accrued what the study authors call “repositories of ecological knowledge,” that can help their entire group survive.
The researchers examined more than 750 hours of killer whale video.
They saw that older, wizened females were the individuals most likely to lead younger whales to salmon feeding grounds, especially during lean times.
The study is in the journalCurrent Biology.
The work provides the first evidence that the advantage conferred via the knowledge held by elderly female whales may be behind the adaptation for their post-fertility longevity.
In humans, an analogous explanation for post-menopausal longevity is part of what's called “the grandmother effect,” the constellation of attributes that make older women especially valuable to the community.
Whale grandmas appear to be highly valuable, too.
参考译文
女性的可生殖年限存在着生物学上的限制。
而研究人员们也一直致力于从进化的角度研究女性在生殖过后保持长寿的奥秘。
除了人类外，只有短鳍巨头鲸和虎鲸在更年期过后还能活30,40年，有些甚至能活到90岁高龄。
然而相比之下，雄性鲸鱼罕有机会享受如此待遇，它们几乎很少活过50岁。
而现在一项针对虎鲸的研究为我们提供了一些为何进化会造成雌鲸长寿的线索：
年长的雌性会积累一些研究者们称之为“生态知识宝库”的信息，这将帮助它们整个种群繁衍生息。
研究人员们对超过750小时的虎鲸视频资料进行了监测。
他们发现上了年纪，正变得干瘦的个体雌鲸极有可能带领幼鲸前往鲑鱼进食的场所，尤其食物稀缺时更甚。
这项研究已在《当代生物学》杂志上发表。
这项研究首次证明雌鲸长辈掌握的知识优势也许是在繁殖过后保持长寿的奥秘所在。
在人类群体中，经期后的长寿也有着类似的解释，即所谓的“祖母效应”的一部分，这一系列的特质使得年长女性对整个群体而言意义非凡。
这样一想看来鲸鱼奶奶也是块宝。
译文为可可英语翻译，未经授权请勿转载！
重点讲解
1.likely to 可能；或许；大概
Very likely he'd told them he had American business interests.
很可能他已经告诉他们自己拥有美国商业利益。
We aimed the microscope at a likely looking target.
我们把显微镜对准了一个看起来合适的目标。
2.appear to 似乎，好像
By all accounts, Rodger would appear to be a fine fellow.
据说，罗杰是个好小伙。
Most doctors appear to recognize homeopathy as a legitimate form of medicine.
大多数医生似乎都接受顺势疗法是一种合理的医疗手段。
