摘要：来自德国、丹麦、法国、匈牙利和比利时的研究人员，分析了动物园中528种哺乳动物和648种鸟类的数据。这项研究于10月1日发表在《科学进展》期刊上，是迄今为止针对哺乳动物和鸟类成年预期寿命性别差异的最全面研究。
雌性狒狒为雄性首领梳理毛发
一、哺乳动物中雌性的寿命比雄性长12%，但鸟类却相反
美国有线电视新闻网(CNN)2025年10月3日报道，一项新的研究显示，性行为是雌性哺乳动物通常比她们的雄性同类长寿的原因之一。
来自德国、丹麦、法国、匈牙利和比利时的研究人员，分析了动物园中528种哺乳动物和648种鸟类的数据。这项研究于10月1日发表在《科学进展》期刊上，是迄今为止针对哺乳动物和鸟类成年预期寿命性别差异的最全面研究。
研究人员还分析了110个物种的野外种群数据，以验证该结论在自然环境中是否同样成立。
研究发现，在哺乳动物中，成年雌性比雄性长寿12%；而鸟类则呈现相反趋势，成年雄性比雌性长寿5%。
研究发现，无论是哺乳动物还是鸟类，其雌雄寿命差异在野外都比在动物园中更为显著。因为动物园中的恶劣气候、天气等压力因素更少。
摄影师拍到的罕见游隼交配照
二、多种仍存在争议性的理论假说
该研究的合著者、德国莱比锡马克斯·普朗克进化人类学研究所统计人口学研究组负责人、统计与数学生态学家费尔南多·科尔切罗解释道，关于雌雄寿命差异的成因，目前存在多种理论，其中主流理论与性染色体相关。
科尔切罗解释说，这一理论被称为“异配性别假说”。该理论认为，拥有两条X染色体的雌性比拥有一条X染色体和一条Y染色体的雄性更具优势，因为“如果X染色体发生突变，而你只有一条X染色体，本质上就没有‘备份’。因此，这些突变最终会产生有害影响，缩短寿命。”
该假说同样适用于鸟类，但结果是雄性更长寿。鸟类雄性拥有两条Z染色体，这使其比仅拥有一条Z染色体和一条W染色体的雌性更具优势。
但科尔切罗表示，部分动物的寿命趋势存在例外，这促使研究人员探索可能导致差异的其他因素。
研究显示，某些猛禽就不符合鸟类中“雄性更长寿”的规律，动物园中的雌性游隼和鹰比雄性同类寿命更长。
科尔切罗称这种现象“令人困惑”，因为在这些猛禽中，“雌性体型更大，且往往（有时比雄性更频繁地）参与领地防御等活动。但即便如此，雌性依然更长寿。”
由于这些例外仅存在于特定类群中，研究作者认为，部分物种群体“可能已进化出不同的生存策略”。
因此，研究人员进而探究了性选择和繁殖成本与寿命性别差异之间的关联。
公鹿为争夺交配权展开争夺战
三、为争夺配偶而发育的体型更大动物反而不具备寿命优势？
其中“性选择假说”认为，部分雄性动物会消耗能量发展用于争夺和吸引配偶的特征与行为，例如改变体型大小、长出硕大的鹿角或犄角，以及通过争斗争夺雌性。科尔切罗表示，这种行为可能会让它们“牺牲生存的寿命机会”。
研究提到，另一“繁殖成本假说”则认为，孕育、分娩以及抚育后代的过程，可能会对生存造成“成本损耗”。
科学家们发现了支持性选择假说的证据：在拥有多个性伴侣的哺乳动物物种中，雌性比雄性更长寿。科尔切罗表示，这表明“例如，消耗过多能量增大体型以寻找配偶的动物，会带来‘生存的寿命成本’”。
但研究人员分析动物园数据时发现，实际趋势与繁殖成本假说的预期相反。
在动物园中，承担抚育后代职责的雌性往往比雄性长寿。野外种群中也存在同样现象，但研究人员表示相关证据较少。
科尔切罗说：“这似乎与直觉相悖，因为任何有孩子的人都知道，抚育后代需要投入大量精力。人们通常会认为，这种精力投入会以牺牲生存寿命为代价。”
但他补充道，从进化角度来看，这一现象“合情合理”。因为部分科学家认为，承担抚育职责的性别需要更长寿，尤其是当后代高度依赖照料时，抚育者必须确保后代能存活至成年并完成繁殖。
研究人员指出，仅由雌性承担抚育职责的物种，往往也是一夫多妻制物种因此，雄性无论如何都可能处于劣势，因为雄性试图与多个雌性交配会消耗它们更多能量。
澳大利亚悉尼科技大学校长研究员、生态学家佐伊·希罗科斯塔斯10月2日向CNN表示：“这项研究拓展了我们的认知，让我们了解到导致成年寿命性别差异的多种因素之间存在复杂的相互作用。”
美国马里兰大学教授、生物学家杰拉尔德·S·威尔金森也表示:“我认为更有趣的结论是，研究发现了强有力的证据，表明交配制度和雌雄体型差）在很大程度上解释了寿命差异的成因。”
摄影师拍到的长颈鹿罕见交配照片
Female mammals live longer than males because of their sexual behavior, study suggests. By Amarachi Orie on CNN. October 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.
Bigger, not better
One theory, the sexual selection hypothesis, suggests that some male animalsspend their energy developing traits and behavior to compete for and attract mates, such as changing theirphysical size, developing big antlers or horns, and fighting to compete for a female. In doing so, they may be “sacrificing their survival,” Colchero said.
Another, the cost of reproduction hypothesis, suggests that carrying and delivering a child, and providing parental care, can come with a survival cost, according to the study.
The scientists found evidence in support of the sexual selection theory, with female mammals living longer than males in species that were non-monogamous — having more than one sexual partner. This suggests that spending too much energy trying to build up your size to find mates, for example, has a “cost,” Colchero said.
However, analyzing data from zoos, the researchers found the opposite trend to what they would have expected under the cost of reproduction theory.
Females with childcare responsibilities tended to live longer than males in zoos. This was the same in the wild, although the researchers said they had less evidence for this.
“This seems to be counterintuitive because, for anyone that has babies, you know that the energy that you put in care — you have to put a lot of energy. And you would imagine that that energy would come at the expense of survival,” Colchero said.
However, he added that it “does make sense” in terms of evolution, since some scientists have argued that the sex doing the caregiving needs to survive longer, especially if the offspring is highly dependent, as the caregiver has to ensure that the child can survive to adulthood and reproduce themselves.
The species in which only the females take on childcare also tend to be species that are polygamous, with the males trying to mate with many females. Therefore, it could also be that the males are at a disadvantage regardless, because they are spending more energy mating, the researchers noted.
“This study expands our knowledge of the complex interplay of factors that contribute to sex differences in adult lifespan, including heterogametic sex determination,” ecologist Zoe Xirocostas, a chancellor’s research fellow at the University of Technology Sydney in Australia, told CNN on Thursday.
While the study lends “further evidence in support of the heterogametic sex hypothesis,” it “mainly considers other evolutionary drivers of sex differences in lifespan that may be just as important, such as parental care and mating system,” Xirocostas, who was not involved in the study added, highlighting the “impressive” breadth of species covered, “including groups with limited coverage in previous studies.”
Biologist Gerald S. Wilkinson, a professor at the University of Maryland, who was not involved in the research, also said the “impressive” study “provides some additional support in favor of the heterogametic sex hypothesis for which sex is expected to have a shorter lifespan.”
“But, I think the more interesting result is that they found strong evidence indicating that the mating system and sexual size dimorphism explain much of the life expectancy variation,” Wilkinson added.
“That is somewhat surprising given that mating systems in zoos are not often typical of what happens in the wild. This result indicates that factors that influence lifespan persist even in controlled environments,” he continued.
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