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  3. Most people think of zoos as safe places for animals, where struggles such as difficulty finding food and avoiding predators (猛兽

Most people think of zoos as safe places for animals, where struggles such as difficulty finding food and avoiding predators (猛兽

admin2012-01-27  104
问题     Most people think of zoos as safe places for animals, where struggles such as difficulty finding food and avoiding predators (猛兽) don’t exist. Without such problems, animals in zoos should live to a ripe old age.
    But that may not be true for 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.
    To learn more about how captivity (圈养) 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. These records made it possible for the researchers to analyze 40 years of data on 800 African and Asian elephants in zoos across Europe.
    The team found that female African elephants bora 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 lived 41.7 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 (肥胖) may be to blame. Zoo elephants don’t get the same kind of exercise they would in the wild, and most are very fat. Social lives of elephants 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.
What is the finding of the study?
选项 A、Female elephants born in the zoo die much earlier than those in the wild.
B、Wild female Asian elephants live longer than their African counterparts.
C、Most wild elephants were killed by predators instead of dying of natural causes.
D、Baby elephants raised in the zoo are less likely to suffer from natural diseases.
答案A
解析 根据题干中的finding将本题出处定位到第4段。该段提到，这些科学家发现，在动物园出生的非洲雌象平均活了16．9年。它们的同伴即那些自然死亡的野生大象平均活了56年——寿命是动物园大象的3倍多。亚洲雌象的情况类似。根据平均寿命可知，动物园出生的雌象比野生雌象死得早，故答案为[A]。研究发现中提及动物园出生的大象与野生大象的寿命对比情况，并未提及亚洲野生象与非洲野生象的寿命对比情况，故排除[B]。[C]与文中提到的Their wild counterparts who died of natural causes矛盾，故排除。[D]在文中未提及。
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