研究表明，雌性哺乳動物比雄性壽命更長，這與性行為有關 (1/2)

 Recently Google News on-line picked up the following:

Female mammals live longer than males because of their sexual behavior, study suggests (1/2)

CNN - By Amarachi Orie

Oct 3, 2025

Sexual behavior is one reason why female mammals typically live longer than their male counterparts, according to a new study.

Researchers from Germany, Denmark, France, Hungary and Belgium analyzed data relating to 528 mammal species and 648 bird species in zoos, in the most comprehensive study to date on sex differences in adult life expectancy in mammals and birds, published in the journal Science Advances on Wednesday.

They also analyzed data on populations in the wild for 110 species, to see if the findings would be the same in natural settings.

Among mammals, adult females lived 12% longer than males, the study found. However, the opposite trend was found among birds, with adult males living 5% longer.

The differences in longevity between the sexes were much more pronounced in the wild than in zoos for both mammals and birds, as there were fewer stressors, such as harsh climates and predators, in zoos, the study said.

Competing theories

There are several theories about why there are these sex differences in longevity. A leading theory relates to the sex chromosomes, explained study co-author Fernando Colchero, a statistical and mathematical ecologist who leads the Statistical Demography Group at Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

In this theory, known as the heterogametic sex hypothesis, it is thought that females, who have two X chromosomes, have an advantage over males, who have one X chromosome and a Y chromosome, because “if there are mutations in the X chromosome, if you only have one copy of that X chromosome, you don’t have a backup essentially. So, those mutations will eventually be harmful and reduce your longevity,” Colchero told CNN.

The same is thought to apply to birds, but with males living longer. They have two Z chromosomes, giving them an advantage over females, which have only one Z chromosome, along with one W.

However, there were exceptions to the longevity trends among some animals, leading the researchers to explore other factors that could also be causing the differences, Colchero said.

For example, some birds of prey did not conform to the male advantage among birds, with female falcons and hawks in zoos outliving their male counterparts, according to the study.

Colchero described this as “puzzling” because, among these animals, “the females are the largest, the females tend to engage more — sometimes more than the males — in territorial defenses and things like that. But, still, the females are the ones that live longer.”

Since these exceptions were found among particular families, the study authors suggested that some groups “may have evolved different strategies.”

They therefore looked at how sexual selection and the cost of reproduction relate to the sex differences in life expectancy.

(to be continued)

研究表明，雌性哺乳動物比雄性壽命更長，這與性行為有關 (1/2)

一項新研究表明，性行為是使雌性哺乳動物通常比雄性壽命更長的原因之一。

來自德國、丹麥、法國、匈牙利和比利時的研究人員分析了動物園中528種哺乳動物和648種鳥類的數據，這是迄今為止關於哺乳動物和鳥類成年預期壽命性別差異的最全面的研究，該研究於週三發表在《科學進展》雜誌上。

他們也分析了110個物種的野生族群數據，以驗證在自然環境中是否也存在相同的結果。

研究發現，在哺乳動物中，成年雌性的壽命比雄性長12%。然而，鳥類的趨勢卻相反，成年雄性的壽命比雌性長5%。

研究表明，無論是哺乳動物還是鳥類，在野外，兩性壽命的差異都比在動物園裡明顯得多，因為動物園裡的壓力源（例如惡劣的氣候和捕食者）較少。

 

不同的的理論

關於兩性壽命差異的原因，目前有幾種理論。該研究的共同作者、統計和數學生態學家、德國萊比錫馬Max Planck 進化人類學研究所統計人口統計小組負責人Fernando Colchero解釋說，一種主流理論與性染色體有關。

這個理論被稱為異配性別假說，認為擁有兩條X染色體的雌性比擁有一條X染色體和一條Y染色體的雄性更具優勢，因為, Colchero告訴CNN:「如果X染色體發生突變，而你只有一個X染色體拷貝，那麼你實際上就沒有備份。因此，這些突變最終會造成損害，縮短你的壽命」。

同樣的道理也適用於鳥類，但雄性壽命較長。它們擁有兩條Z染色體，這使其比只有一條Z染色體和一條W染色體的雌性更具優勢。

然而，Colchero表示，一些動物的長壽趨勢也存在例外，促使研究人員探索其他可能導致這種差異的因素。

例如，一些猛禽並不符合鳥類中雄性優勢的規律，研究表明，動物園裡的雌性獵鷹和雌鷹的壽命比雄性更長。

Colchero稱這 “令人費解” ，因為在這些動物中， “雌性體型最大，而且雌性往往較多（有時甚至比雄性更多）參與領土防禦等活動。但雌性仍然是壽命更長的。”

由於這些例外情況只存在於某些家族中，研究作者認為，一些群體「可能進化出了不同的策略」。

因此，他們研究了性選擇和生殖成本與預期壽命的性別差異之間的關係。

（待續）