科学美国人60秒:雌鲸长寿同自身掌握知识有关-托福听力下载

　　科学美国人60秒中文翻译：

　　Women have a biological cap on their reproductive years. 女性的可生殖年限存在着生物学上的限制。

　　And from an evolutionary standpoint researchers have long wondered why human female longevity extends well past fertility. 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。

　　Other than humans, only short-finned pilot whales and killer whales live three or more decades after menopause, some even reaching their 90s. 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。

　　Male whales, which are far less likely to be followed by group-mates than are females, seldom survive past 50. 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。

　　Now a study of killer whales offers some clues about why evolution may have selected for such long life: 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：

　　older females have accrued what the study authors call repositories of ecological knowledge, that can help their entire group survive. 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。

　　The researchers examined more than 750 hours of killer whale video. 研究人员们对超过750小时的虎鲸视频资料进行了监测。

　　They saw that older, wizened females were the individuals most likely to lead younger whales to salmon feeding grounds, especially during lean times. 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。

　　The study is in the journalCurrent Biology. 这项研究已在《当代生物学》杂志上发表。

　　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. 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。

　　In humans, an analogous explanation for post-menopausal longevity is part of what's called the grandmother effect, 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，

　　the constellation of attributes that make older women especially valuable to the community. 这一系列的特质使得年长女性对整个群体而言意义非凡。

　　Whale grandmas appear to be highly valuable, too. 这样一想看来鲸鱼奶奶也是块宝。

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