當奶奶在身邊的時候，年輕的虎鯨吃得更好，活得更久

當奶奶在身邊的時候，年輕的虎鯨吃得更好，活得更久

It's hard to measure how much we benefit from the influence of a grandmother.

很難衡量我們從祖母的影響中獲益多少。

Grandmothers have a wealth of wisdom and experience — and that translates into all kinds of valuable life lessons.

祖母們擁有豐富的智慧和經(jīng)驗，這些都轉(zhuǎn)化為各種寶貴的人生經(jīng)驗。

When it comes to keeping the little ones safe, grandmother may indeed know best. (Photo: Tory Kallman/Shutterstock)

We're hardly the only species to value them. In fact, their generational influence may play a critical role in orca society.

我們并不是唯一珍視它們的物種。事實上，它們的世代影響可能在虎鯨社會中扮演著重要的角色。

A study published this week in the Proceedings of the National Academy of Sciences suggests the elder whales are a key factor in keeping their grandkids alive, especially when food is scarce.

本周發(fā)表在《美國國家科學院院刊》雜志上的一項研究表明，年長的鯨魚是維持孫輩生存的關(guān)鍵因素，尤其是在食物匱乏的情況下。

The survival rates of those young whales improve even more dramatically if the grandmother has already gone through menopause.

如果祖母已經(jīng)經(jīng)歷了更年期，那么這些小鯨魚的存活率會有更顯著的提高。

That's particularly surprising since menopause among most animal species is typically associated with the tail end of life. Not so, however, with humans and some whales — including orcas, which can live decades beyond menopause.

這尤其令人驚訝，因為大多數(shù)動物物種的更年期通常與生命的結(jié)束有關(guān)。然而，人類和一些鯨魚，包括逆戟鯨，卻不是這樣。逆戟鯨可以在更年期后存活幾十年。

Now, it seems that added longevity has an evolutionary purpose. Grandmother whales live long after they've stopped being able to produce their own offspring, and their continued presence ensures the children of their children grow up strong and healthy.

現(xiàn)在看來，延長壽命有一個進化的目的。祖母鯨在停止繁殖后代后仍能活很長時間，它們的繼續(xù)存在確保了它們孩子的健康成長。

It's possible that grandmother orcas simply have more time to spare. (Photo: Leonardo Gonzalez/Shutterstock)

For their research, scientists analyzed decades of census data on orca populations around Washington state and British Columbia. Orca calf mortality, they noted, rose sharply in the years following the death of a post-menopausal grandmother. But calves that still lived with their grandmas enjoyed a much higher rate of survivability.

在他們的研究中，科學家分析了華盛頓州和不列顛哥倫比亞省附近虎鯨種群數(shù)十年的普查數(shù)據(jù)。他們注意到，在一位絕經(jīng)后的祖母去世后的幾年里，逆戟鯨的幼鯨死亡率急劇上升。但是那些仍然和奶奶住在一起的小牛存活率要高得多。

The researchers suspect post-menopausal grandmothers simply have more time to dote on the young ones, caring for them as a kind of nanny and making sure they have enough food to eat.

研究人員猜測，絕經(jīng)后的祖母們只是有更多的時間來溺愛年輕的孩子，把她們當作保姆一樣照顧，并確保她們有足夠的食物吃。

"The study suggests that breeding grandmothers are not able to provide the same level of support as grandmothers who no longer breed," lead author Dan Franks, a biologist at the U.K.'s University of York tells Agence France-Presse. "This means that the evolution of menopause has increased a grandmother's capacity to help her grand-offspring."

研究報告的主要撰寫人、英國生物學家丹•弗蘭克斯說:“研究表明，生育能力強的祖母無法提供與不生育能力強的祖母同樣的支持。約克大學的教授告訴法新社。“這意味著更年期的進化提高了祖母幫助孫輩的能力。”

Humans may recognize this phenomenon as the "grandmother effect": Women who retain their strength after the decline of fertility have traditionally helped their daughters care for the children.

人們可能把這種現(xiàn)象稱為“祖母效應”:在生育能力下降后仍然保持體力的女性傳統(tǒng)上幫助女兒照顧孩子。

"This is the first non-human example of the grandmother effect in a menopausal species," Franks adds.

弗蘭克斯補充說:“這是首次在更年期物種中發(fā)現(xiàn)祖母效應。”

"It has also been shown in elephants, but they are able to reproduce until the end of their lives. We currently know of only five species that go through menopause: the others are short-finned pilot whales, narwhals and beluga."

“這在大象身上也有體現(xiàn)，但它們能夠繁殖直到生命結(jié)束。目前我們只知道有五種動物進入更年期:其他的是短鰭領(lǐng)航鯨、獨角鯨和白鯨。”

Now, how exactly does one know when a post-menopausal orca granny is spreading her life-affirming cheer to the rest of the pod?

現(xiàn)在，我們?nèi)绾未_切地知道一個絕經(jīng)后的虎鯨奶奶是什么時候把她的生命肯定的歡呼傳播到豆莢的其余部分?

The researchers looked at 378 individual whales known to have a maternal grandmother. In the cases where a grandmother had died within the previous two years, the mortality rate for a young whale jumped by 4.5 times.

研究人員觀察了378頭已知有外祖母的鯨魚個體。在前兩年祖母去世的案例中，年輕鯨魚的死亡率上升了4.5倍。

And in times of food scarcity, the "grandmother effect" was particularly pronounced.

在糧食短缺時期，“祖母效應”尤為明顯。

"We have previously shown that post-reproductive grandmothers lead the group around foraging grounds, and that they are important in doing that in times of need, when the salmon are scarce," Franks explains to AFP.

弗蘭克斯向法新社解釋說:“我們之前的研究表明，繁殖后的祖母會帶領(lǐng)這群鮭魚四處覓食，而且在鮭魚稀少的時候，她們在這方面很重要。”

"They are also known to directly share food with younger relatives. We also suspect babysitting."

他們還會直接與年輕的親戚分享食物。我們還懷疑他們是保姆。”