辛达雅思代报考位，雅思代报名截止前提醒广大考生抓紧时间报名，欢迎前来咨询在线客服。

       下文选自National Geographic, 关于濒危动物的文章，难度和篇幅均与雅思阅读考试相当，而且有意识地选择过期的期刊(back issue), 用于训练快速阅读能力，希望有助于大家备考雅思阅读。

　　One in Four Mammals at Risk of Extinction

　　Kimberly Johnson

　　for National Geographic

　　October 6, 2008

　　One in four of the world's 5,487 known mammal species face extinction, according to a new conservation "report card" unveiled today.

　　Marine mammals face even steeper odds, with one in three species at risk of disappearing, according to the study.

　　The assessment, done as part of the International Union for Conservation of Nature's (IUCN's) Red List of Threatened Species, took more than 1,700 experts from 130 countries five years to complete.

　　The report's findings were released today in conjunction with this week's IUCN meeting in Barcelona, Spain, and will appear later this week in the journal Science. "Our results paint a bleak picture of the global status of mammals worldwide," the study authors wrote.

　　Humans are mostly to blame, as habitat loss, pollution, and hunting continue to squeeze at-risk species.

　　Under Threat

　　The new report updates the last IUCN survey conducted in 1996 and adds 700 species not previously assessed.

　　"Perversely, the species that humans show greatest affinity toward—the largest mammals such as primates, big cats, and whales—are significantly more likely to be threatened with extinction," Barney Long, a biologist at the World Wildlife Fund in Washington, D.C., said in an email.

　　Some of the most threatened species are found in Asia, a region undergoing rapid human population and economic growth.

　　"This is leading to habitat loss due to agricultural expansion; development of infrastructure such as roads, which fragment critical landscapes; and increasing areas for industrial crops such as oil palm and pulp for paper," said Long, who helped create the new assessment.

　　Currently, 79 percent of Asia's primate species face extinction.

　　Worldwide, habitat loss affects roughly 40 percent of threatened mammal species, while human hunting affects 17 percent, Long said.

　　Seventy-eight percent of marine mammals are threatened by accidental deaths, such as becoming bycatch in fishing nets intended for other species.

　　Marine mammals are "threatened purely because humankind does not care enough to mitigate deaths that do not even benefit our species," Long said.

　　"All these threats represent human-driven activities that, if not controlled, will soon lead to a dramatic increase in the 76 species of mammal that are known to have gone extinct since 1500," Long said.

　　Restoration

　　Timothy Ragen is executive director of the U.S. government's Marine Mammal Commission in Bethesda, Maryland.