Longer Lives for Wild Elephants
Most people think of zoos as safe places for animals，where struggles such as difficulty finding food and avoiding predators don’t exist. Without such problems，animals in zoos should live to a ripe old age1.
But that may not be true for2 the largest land animals on Earth. Scientists have known that elephants in zoos often suffer from poor health. They develop diseases，joint problems and behavior changes. Sometimes, they even become infertile，or unable to have babies.
To learn more about how captivity affects elephants，a team of international scientists compared the life spans of female elephants born in zoos with female elephants living outdoors in their native lands. Zoos keep detailed records of all the animals in their care，documenting factors such as birth dates, illnesses, weight and death. These records made it possible for me researchers to analyze 40 years of data on 800 African and Asian elephants in zoos across Europe. The scientists compared the life spans of the zoo-born elephants with the life spans of thousands of female wild elephants in Africa and Asian elephants that work in logging camps3，over approximately the same time period.
The team found that female African elephants born in zoos lived an average of 16.9 years. Their wild counterparts who died of natural causes lived an average of 56 years-more than three times as long. Female Asian elephants followed a similar pattern. In zoos，they lived 18.9 years，while those in the logging camps lived41.7 years.
Scientists don't yet know why wild elephants seem to fare so much better than their zoo-raised counterparts. Georgia Mason，a biologist at the University of Guelph in Canada who led the study，thinks stress and obesity may be to blame4.Zoo elephants don't get the same kind of exercise they would in the wild，and most are very fat. Elephant social lives are also much different in zoos than in the wild，where they live in large herds and family groups.
Another finding from the study showed that Asian elephants born in zoos were more likely to die early than Asian elephants captured in the wild and brought to zoos. Mason suggests stress in the mothers in zoos might cause them to have babies that are less likely to survive.
The study raises some questions about acquiring more elephants to keep in zoos. While some threatened and endangered species living in zoos reproduce successfully and maintain healthy populations，that doesn't appear to be the case with elephants. "Currently，zoos are net consumers of elephants，not net producers," Mason says.
詞匯：
predator n.食肉動物 captivity/ n.監(jiān)禁;束縛
ripe adj.成熟的 fare v.過活，生活
infertile adj.不生育的 obesity n.過度肥胖;肥胖癥
注釋：
1.1ive to a ripe old age：這是一種固定用法，意思是live to an age that is considered to be very
old(長壽，高壽)。
2.be true for：或者be true of：對……適用。短文中第二段第一句：But that may not be true for
the largest land animals on Earth.這里，作為主語的that指的是第一段所陳述的內(nèi)容。這個句子要傳達的意思是：動物園對其他動物來說是一個安棲之地，而對大象來說卻不然。
3.logging camps：伐木場。Logging作為名詞，意思是：伐木業(yè)。
4.stress and obesity may be to blame：壓力和肥胖是問題的根源。be to blame：該受責備，應(yīng)承擔責任。
練習：
1.According to the first two paragraphs，unlike other zoo animals，zoo elephants
A.have difficulty eating food.
B.1ive to a ripe old age.
C.are not afraid of predators.
D.develop health problems.
2.Which of the following about the international scientists' research on the life spans of elephants is NOT true?(See paragraph 3)?
A.They compared zoo elephants with wild elephants.
B.They kept detailed records of all the elephants in their care.
C.They analyzed the records of the elephants kept in zoos.
D.The zoo-born elephants they studied are kept in European zoos.
3.What do the scientist find in their research?
A.Female elephants live longer than male elephants.
B.Female zoo elephants live longer than their wild counterparts.
C.Female zoo elephants die much earlier than their wild counterparts.
D.Elephants in zoos and those in the wild enjoy the same long life spans.
4.What are the possible causes of stress and obesity Zoo-raised elephants generally suffer from?
A.They do not like living in herds.
B.They do not get enough exercise.
C.They do not live with their families.
D.Both B and C.
5.Which of the following does the author suggest in the last paragraph 7?
A.It may not be a wise policy to keep elephants in the zoo.
B. Elephants are no longer an endangered species.
C.Zoo-born elephants should be looked after more carefully.
D.Zoos should keep more animals except elephants.
答案與題解：
1.D 短文的第一段告訴我們，人們通常認為動物園內(nèi)的動物沒有獵食的困難，也不受其他獵食動物的威脅，所以一般壽命較長。但第一段并沒有提及大象。第二段則說，動物園內(nèi)的大象卻不然，它們面臨很多健康問題。所以，除了D以外，其他選項均不符合這兩段內(nèi)容。
2.B 第三段告訴我們，動物園，而不是這些研究人員，保存了所有園內(nèi)動物的詳細相關(guān)信息。所以應(yīng)該選擇B。其他三個選項均能在該段中找到相關(guān)內(nèi)容。
3.C 短文的第四段提供了答案。該段告訴我們，野生的雌性大象的平均壽命是動物園里的雌性大象平均壽命的3倍還多。
4.D 短文的第五段提供了答案。該段第三句的意思是：動物園里的大象不像野生大象那樣活動，因此非常肥胖。他們也不像野生大象那樣過著群居的生活，即live in herds and family groups。
5.A 短文通篇陳述了大象在動物園內(nèi)的生存問題，最后一段是全文的總結(jié)。該段第一句指出，對動物園大象的研究向人們提出了一個問題：是否應(yīng)該將更多的大象關(guān)進動物園。該段還重復了第一、第二段的觀點：其他動物在動物園能夠很好地繁衍生息，而大象卻不能。所以，A是正確選擇。B、C、D均沒有在文中被提及。