Efforts to rescue the tiger from the brink of extinction should focus on protecting populations of the big cat in a few key sites, researchers have urged.
Conservationists warned the species was facing its "last stand", with fewer than 3,500 tigers in the wild - of which just 1,000 are breeding females.
But protecting 42 sites, which cover just 6% of the animal's available habitat, would directly defend almost 70% of the world's remaining tigers and should be the immediate priority for conservation efforts.
Writing in the journal PLoS Biology, the researchers said over-hunting of tigers and their prey had driven the decline in the big cat, while loss of habitat was also a factor.
The apparent success of reserves established in the 1970s to protect the tiger had led many conservation experts to shift their focus to attempts to preserve the cat well outside these protected areas.
But protection and management in reserves was inadequate and the increased demand for tiger parts for traditional medicine in Asia meant that populations crashed in the face of poaching outside and inside the protected areas.
Professor Nigel Leader-Williams, from the University of Cambridge's department of geography, who contributed to the study, said: "The long-term goal is to conserve an Asia-wide network of large landscapes where tigers can flourish.
"The immediate priority, however, must be to ensure that the few breeding populations still in existence can be protected and monitored.
"Without this, all other efforts are bound to fail."
The researchers said tigers were mostly restricted to small pockets in protected areas, with 42 places identified as "source sites" which contain breeding populations that have the potential to repopulate larger areas.