China is home to at least 551 species of mammals (the third-highest such number in the world), 1,221 species of birds (eighth), 424 species of reptiles (seventh) and 333 species of amphibians (seventh). Wildlife in China shares habitat with, and bears acute pressure from, the world's largest population of humans. At least 840 animal species are threatened, vulnerable or in danger of local extinction in China, due mainly to human activity such as habitat destruction, pollution and poaching for food, fur and ingredients for traditional Chinese medicine. Endangered wildlife is protected by law, and , the country has over 2,349 nature reserves, covering a total area of 149.95 million hectares, 15 percent of China's total land area. Most wild animals have been eliminated from the core agricultural regions of east and central China, but they have fared better in the mountainous south and west. The Baiji was confirmed extinct on 12 December 2006.