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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  77
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.
Unlike other zoo animals, zoo-raised elephants______.
选项 A、have difficulty getting food
B、live a very long life
C、give birth to many babies
D、develop health problems
答案D
解析 根据题干中的zoo-raised elephants将本题出处定位到第2段。该段首先提到，对于陆地上最大的动物来说，事情却并非如此。科学家已经发现，动物园里的大象的健康状况经常很差，随后具体说明：它们生病，关节有问题，行为发生改变……甚至会失去生育能力。由此可知，动物园饲养的大象会产生很多健康问题，故答案为[D]。由首段首句可知，在动物园里，类似猎食困难等问题并不存在，[A]与之矛盾。首段提到“动物园内的动物应该都会活得很长”，再结合第2段首句提到的“但是，对于陆地上最大的动物来说，事情却并非如此”可知，动物园的大象不会活得很长，故排除[B]。由第2段提到的“动物园饲养的大象的健康状况经常很差……有时候，它们甚至会失去生育能力”可排除[C]。
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大学英语四级

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