The World Wildlife Fund, an international conservation group, says more than two-thirds of the world's wildlife could be gone by the year 2020. The organization says there's already been a 58 percent decrease in the number of fish, mammals, birds and

发表于:2018-12-19 / 阅读(57) / 评论(0) 分类 CNN美国有线新闻2016年11月

Highway Crossings Protect Migrating Pronghorns--and Motorists Ever hear of the pronghorn antelope in the American west? Well, its not really an antelopeits actually more closely related to giraffes than to true antelopes. And the last known migration

发表于:2019-02-03 / 阅读(70) / 评论(0) 分类 2018年科学美国人10月