Now a study of killer whales offers some clues about why evolution may have selected for such long life（為什么進化會造成雌鯨長壽）: 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 journal Current 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.
a biological cap：一個生理限制
an evolutionary standpoint：一個進化的角度
wonder：vt 對…好奇，想弄明白? n 奇跡，奇觀? adj 神奇的
longevity: n 長壽，長期供職，壽命
short-finned pilot whales：短鰭領航鯨 killer whales
accrue: vi 增加，積累? vt 增值
repository: n 倉庫
lean times: 貧瘠時代
post-fertility longevity 生育后的長壽
attribute：vt 認為，把什么歸于 n 屬性，特征，價值