http://www.vox.com/2014/9/30/6870749/the-world-has-lost-half-its-wildlife-since-1970-wwf-says
"Earth has lost a lot of animals over the past four decades. A major new study by the World Wildlife Fund estimates that the overall number of mammals, birds, reptiles, amphibians and fish has declined 52 percent between 1970 and 2010."
"Earth has lost a lot of animals over the past four decades. A major new study by the World Wildlife Fund estimates that the overall number of mammals, birds, reptiles, amphibians and fish has declined 52 percent between 1970 and 2010."
