2022年【2022职称英语考试理工类B级阅读文章二】职称英语理工a,b哪个高.doc

2022年【2022职称英语考试理工类B级阅读文章二】职称英语理工a,b哪个高职称英语网权威发布2022职称英语考试理工类B级阅读文章二，更多2022职称英语考试理工类B级阅读文章二相关信息请访问职称英语考试网。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 But mat may not be true for2 the largest land animals on Earth. Scientists have known that elephants in zoos often suffer from poor healthThey develop diseases，joint problems and behavior changesSometimesthey even become infertileor 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 landsZoos keep detailed records of all the animals in their care，documenting factors such as birth dates，illnesses，weight and deathThese records made it possible for the researchers to analyze 40 years of data on 800 African and Asian elephants in zoos across EuropeThe scientists compared the life spans of the zooborn 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 l 6.9 yearsTheir wild counterparts who died of natural causes lived an average of 56 yearsmore than three times as longFemale Asian elephants followed a similar patternIn zoos, they lived l 89 s years, while those in the logging camps lived 41.7 years Scientists dont yet know why wild elephants seem to fare so much better than their zoo-raised counterpartsGeorgia Mason，a biologist at the University of Guelph in Canada who led the study, thinks stress and obesity may be to blame4Zoo elephants dont get the same kind of exercise they would in the wild，and most are very fatElephant 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 zoosMason 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 zoosWhile some threatened and endangered species living in zoos reproduce successfully and maintain healthy populations，that doesnt appear to be the case with elephants"Currently，zoos are net consumers of elephants，not net producers，" Mason says 词汇： Predator n食肉动物 Ripe adj成熟的 Infertile adj不生育的 Captivity n监禁；束缚 Fare v过活，生活 Obesity adj过度肥胖；肥胖症第 3 页 共 3 页