Researchers already know that women live longer than men in all parts of the world.
研究人員已經知道，全球各地的女性壽命都比男性長。
Scientists have largely linked the difference in life expectancy between the sexes to biological survival factors.
科學家們認為，男女預期壽命差異很大程度上與生物學上的生存因素有關。
Now, a new study of wild mammals has found great differences in length of life and aging in many species of mammals.
現在，一項關於野生哺乳動物的新研究發現，許多哺乳類動物的壽命和衰老都存在巨大差異。
The researchers found that, in humans, women live almost 8 percent longer than men.
研究人員發現，對於人類來說女性的壽命比男性的要長近8%。
But among wild mammals, females in 60 percent of the studied species live, on average, 18.6 percent longer.
但對於野生哺乳動物來說，60%的研究物種中雌性預期壽命（比雄性）長18.6%。
The percentages are very different for different groups of mammals.
不同哺乳類動物群體的比例差異也很大。
Jean-Francois Lemaitre led the study. He is from the University Lyon 1 in France.
來自法國裡昂第一大學的讓·弗朗索瓦·勒梅特（Jean-Francois Lemaitre）領導了這項研究。
He and his research team collected information on age-related deaths for 134 groups of 101 wild species of mammals.
他和他的研究小組收集了134組101種野生哺乳動物與年齡相關的死亡信息。
Lemaitre said, 「It was surprising to observe that this gender gap in lifespan often exceeds the one observed in
humans and is, at the same time, extremely variable across species.」
勒梅特說：「令人驚訝的是，這種壽命的性別差異往往超出了在人類身上所觀察到的差異，同時在不同種族之間也存在非常大的差距。」
Tamas Szekely, from the University of Bath, was one of the writers of the study.
巴斯大學的塔瑪斯·塞凱利是該研究的作者之一。
He told VOA that female lions in the wild live at least 50 percent longer than male lions.
他告訴美國之音，野生的雌獅比雄獅的壽命至少長50%。
「We previously thought this was mostly due to sexual selection, he said. 「However our data do not support this.」
「我們之前一直以為這主要是由於性別選擇，」他說，「然而，我們的數據並不支持這一觀點。」
Scientists say the risk of death does not increase more quickly in males than in females across species.
科學家表示，在不同的物種中，雄性的死亡風險並沒有比雌性增加更快。
They say there must be other, more complex reasons.
他們認為，肯定還有其他更複雜的原因。
These include things such as environmental conditions in which the animals live, sex-specific growth, survival and reproduction through the history of the species.
包括諸如動物生活的環境條件，性別特異性增長，物種生存和繁殖的歷史等因素。
Szekely suggests that one reason for the differences between the sexes is that 「female survival increases when males provide some or all of the parental care.」
塞凱利表示，造成性別差異的原因之一是「當雄性提供部分或全部的親代撫育責任時，雌性的存活率就會提高。」
He added that 「giving birth and caring for young becomes a significant health cost for females
他補充道：「對女性來說，生育和照顧年輕一代會導致大量健康損耗，
and so this cost is reduced if both parents work together to bring up their offspring."
因此如果父母雙方共同努力撫養後代，女性的損耗將會減少。」
Scientists plan to compare the data on wild mammals with the data on mammals kept in zoos.
科學家計劃將野生哺乳動物的數據與動物園飼養的哺乳動物的數據進行比較。
They want to measure how much biological differences between the sexes affect life expectancy.
他們希望藉此衡量性別差異對兩性之間預期壽命的影響。
In zoos, animals do not have to fight with predators or fight for food and mates.
在動物園，動物們無需對抗掠食者，也不必為了食物與配偶爭鬥。
Scientists hope the findings will give them a better understanding of what affects length of life in humans.
科學家希望，這些發現能幫助他們更好地了解影響人類壽命的因素。
In the past 200 years, the average life expectancy of humans has more than doubled.
在過去200年間，人類的預期壽命增長了一倍多。
The main reasons for the increase are improved living conditions and developments in the field of medicine.
造成這一現象的主要原因是生活條件的改善和醫學領域的發展。
However, women continue to live longer than men. This suggests biological differences also play a part.
然而，女性的壽命仍然比男性長，這表明生物學差異也起到了一定作用。
The U.S. Centers for Disease Control says the average American man will live to age 76. The average woman in America will live to age 81.
美國疾病控制中心表示，美國男性的平均壽命為76歲，美國女性的平均壽命為81歲。
Women can also expect to be healthier than men in their older years. Experts said this is because of a combination of biological and social differences.
女性在老年階段也會比男性更加健康。專家表示，這是由於生物和社會的差異造成的。
A hormone in men called testosterone is connected to a decrease in their immune system and risk of heart-related
diseases as they age.
男性體內的一種叫做睪丸素的激素與他們的免疫系統下降和隨著年齡增長患心臟病的風險有關。
It is also connected to risky behavior, such as smoking, drinking and unhealthy eating habits.
壽命還與一些危險的行為習慣有關，如吸菸、飲酒和不良的飲食習慣。
Men are also less likely than women to follow suggestions and warnings from a doctor.
女性比男性更願意聽從醫生的建議和警告。
And research shows that men are more likely to take life-threatening risks and to die in car accidents or gun
fights. 研究表明，男人更願意冒風險，更容易死於車禍或槍戰。