为什么女性比男性更长寿?
文章来源:未知 文章作者:enread 发布时间:2020-04-26 09:17 字体: [ ]  进入论坛
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研究人员已经知道,全球各地的女性寿命都比男性长。科学家们认为,男女预期寿命差异很大程度上与生物学上的生存因素有关。
Researchers already know that women live longer than men in all parts of the world. Scientists have largely linked the difference in life expectancy1 between the sexes to biological survival factors.
Now, a new study of wild mammals has found great differences in length of life and aging in many species of mammals.
The researchers found that, in humans, women live almost 8 percent longer than men. But among wild mammals, females in 60 percent of the studied species live, on average, 18.6 percent longer. The percentages are very different for different groups of mammals.
Jean-Francois Lemaitre led the study. He is from the University Lyon 1 in France. He and his research team collected information on age-related deaths for 134 groups of 101 wild species of mammals.
Lemaitre said, "It was surprising to observe that this gender2 gap in lifespan often exceeds the one observed in humans and is, at the same time, extremely variable across species."
Tamás Székely, from the University of Bath, was one of the writers of the study. He told VOA that female lions in the wild live at least 50 percent longer than male lions.
"We previously3 thought this was mostly due to sexual selection, he said. "However our data do not support this."
Scientists say the risk of death does not increase more quickly in males than in females across species. They say there must be other, more complex reasons. These include things such as environmental conditions in which the animals live, sex-specific growth, survival and reproduction through the history of the species.
Székely suggests that one reason for the differences between the sexes is that "female survival increases when males provide some or all of the parental4 care."
He added that "giving birth and caring for young becomes a significant health cost for females and so this cost is reduced if both parents work together to bring up their offspring."
Scientists plan to compare the data on wild mammals with the data on mammals kept in zoos. They want to measure how much biological differences between the sexes affect life expectancy. In zoos, animals do not have to fight with predators5 or fight for food and mates.
Scientists hope the findings will give them a better understanding of what affects length of life in humans. In the past 200 years, the average life expectancy of humans has more than doubled. The main reasons for the increase are improved living conditions and developments in the field of medicine. However, women continue to live longer than men. This suggests biological differences also play a part.
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. 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.
A hormone6 in men called testosterone is connected to a decrease in their immune system and risk of heart-related diseases as they age. It is also connected to risky7 behavior, such as smoking, drinking and unhealthy eating habits.
Men are also less likely than women to follow suggestions and warnings from a doctor. And research shows that men are more likely to take life-threatening risks and to die in car accidents or gun fights.


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1 expectancy tlMys     
n.期望,预期,(根据概率统计求得)预期数额
参考例句:
  • Japanese people have a very high life expectancy.日本人的平均寿命非常长。
  • The atomosphere of tense expectancy sobered everyone.这种期望的紧张气氛使每个人变得严肃起来。
2 gender slSyD     
n.(生理上的)性,(名词、代词等的)性
参考例句:
  • French differs from English in having gender for all nouns.法语不同于英语,所有的名词都有性。
  • Women are sometimes denied opportunities solely because of their gender.妇女有时仅仅因为性别而无法获得种种机会。
3 previously bkzzzC     
adv.以前,先前(地)
参考例句:
  • The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
  • Let me digress for a moment and explain what had happened previously.让我岔开一会儿,解释原先发生了什么。
4 parental FL2xv     
adj.父母的;父的;母的
参考例句:
  • He encourages parental involvement in the running of school.他鼓励学生家长参与学校的管理。
  • Children always revolt against parental disciplines.孩子们总是反抗父母的管束。
5 predators 48b965855934a5395e409c1112d94f63     
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面)
参考例句:
  • birds and their earthbound predators 鸟和地面上捕食它们的动物
  • The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》
6 hormone uyky3     
n.荷尔蒙,激素,内分泌
参考例句:
  • Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
  • This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
7 risky IXVxe     
adj.有风险的,冒险的
参考例句:
  • It may be risky but we will chance it anyhow.这可能有危险,但我们无论如何要冒一冒险。
  • He is well aware how risky this investment is.他心里对这项投资的风险十分清楚。
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