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 dont exist. Without such problems, animals in zoos should live to a ripe old agel.
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 the researchers to analyze 40
The team found that female African elephants born in zoos lived an average of l 6.9 years.Their wild counterparts who died of natural causes lived an average of 56 yearsmore than three times as long.Female Asian elephants followed a similar pattern.In zoos, they lived l 8.9 s years, while those in the logging camps lived 41.7 years.
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.
词汇:
Ripe adj.成熟的
Captivity n.监禁;束缚
Obesity adj.过度肥胖;肥胖症
名师推荐2011六级写作满分表达句(8)
四六级考试作文预测必背话题:如何建立节约型社会
名师推荐2011六级写作满分表达句(7)
2012英语六级热点范文:社会不文明现象
四六级考试作文预测必背话题:中国酒驾现象
12月英语六级预测作文:民工涌入大城市
12月英语四六级考试作文万能模版
英语六级作文范文模版(一)
12月英语四六级考试写作经典句型仿写(1)
英语六级写作分段逐句指导之结尾段
英语六级高分必备:文章主题句(1)
最拿分的英语六级写作范文例句精选
大学英语六级并列句和复合句的写作练习
英语六级作文范文模版28篇(二)
四六级考试作文预测必背话题:食品安全问题
四六级考试作文预测必背话题:买彩票
四六级考试作文预测必背话题:出国留学的好处
名师推荐2011六级写作满分表达句(9)
四六级考试作文预测必背话题:考公务员热
名师推荐2011十二月六级写作满分表达句(1)
12月英语六级预测作文:商品过度包装
六级写作-句型
四六级考试作文预测必背话题:假文凭的危害
四六级考试作文预测必背话题:毕业生频繁换工作
四六级考试作文预测必背话题:考研热
四六级考试作文预测必背话题:竞选学生会干部
英语六级写作分段逐句指导之主题句
名师推荐2011六级写作满分表达句(3)
四六级考试作文预测必背话题:大学生使用信用卡
名师推荐2011六级写作满分表达句(2)
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |