They tigers are being lost mostly because of habitat loss or poaching. Tiger bones, eyes, teeth and other parts are used in some Asian countries as medicine for malaria and meningitis. Tiger are also hunted for there skin to be sold by group or individual poachers. Some roads that are built make the tigers territory smaller and prey might be to small for the groups of tigers. The World Wildlife and Wildlife Conservation Society are attempting to get a "top-level" Asian government official to get involved in tiger conservation. Conservation is being helped by individual members of villages who patrol forests to make sure there are no illegal poachers. Also, there are programs in zoos to help increase the tiger population.
Source: Life Science