<p>Scientists estimate only about 3,000 wild tigers are left in the entire world. Tiger territory once stretched from Turkey to the Russian Far East and just a century ago, before the terrible toll of hunting and habitat destruction, 100,000 tigers inhabited the wilds of Asia. Now their descendents hang on in a tiny fraction of their former range, prowling fragmented pockets of habitat where keeping enough tigers alive to breed is increasingly difficult. Three of the nine tiger subspecies (Bali, Javan, and Caspian tigers) became extinct during the 20th century, leaving only the half dozen living species featured in this gallery.</p> <p>Recent studies show in just three tiger generations (21 to 27 years) the big cats' population has shrunk by 50 percent and their range has also been halved. Shrinking space and rampant poaching for traditional Chinese medicine present a formidable challenge to the future of wild tigers.</p> <p>About half of all living tigers are <a href="http://animals.nationalgeographic.com/animals/mammals/bengal-tiger/" target="_blank">Bengal tigers</a> (pictured here), sometimes called Indian tigers because most live in that nation. Others are in Bangladesh, Nepal, Bhutan, China, and Myanmar. Given space and prey<i>Panthera tigris tigris</i> can thrive in many types of forests or grasslands, and the Bengal is the only subspecies that also inhabits mangrove forests, in the Sundarbans island group in the Bay of Bengal.</p> <p>Tigers tend to be solitary animals but where food is plentiful they can be found in relatively great densities, which makes India perhaps the best place to spot them. Bengal tigers are the world's most likely to enjoy an abundance of pigs, deer, and other hoofed prey. An average of 18 tigers can occupy 39 square miles in India's Corbett Tiger Reserve, while only a single Sumatran tiger could survive in that same area, and a male Amur tiger would need 10 times that amount, or 386 square miles.</p> <p><i><b>Big Cats Initiative</b></i></p> <p><i>National Geographic is working to avert the extinction of tigers, lions, cheetahs, and other big cats with the <a href="http://animals.nationalgeographic.com/animals/big-cats/" target="_blank">Big Cats Initiative</a>, a comprehensive program that supports innovative projects. Learn how you can help save these animals.</i></p>