Indian tigers face threat due to lack of genetic diversity. Tigers need genetic diversity to survive. India's tigers are facing extinction owing to a collapse in the variety of their mating partners, say Cardiff University researchers. They found that 93% of DNA variants found in tigers shot the period of the British Raj were not present in tigers today Prof Mike Bruford said the genetic diversity needed for the species to survive had been "lost dramatically". There are fewer than 2,000 tigers left worldwide, 60% in India. The Cardiff university team collaborated with the National Centre for Biological Sciences in Bangalore, India on the research. They had unprecedented access to the Natural History Museum of London's tiger collection which allowed them to identify the DNA variants in the tigers killed in the British Raj period from 1858 to 1947 but which have disappeared today. Mechanised trophy hunting reduced the animal's numbers from 40,000 in a mere 100 years. The territory occupied by the tiger has declined more than 50% during the last three generations and mating now only occurs in 7% of its historical territory. A tiger hunt on the back of elephants in India in 1912 A tiger hunt on the back of elephants in India in 1912 Prof Bruford of the Cardiff School of Biosciences was one of the research's lead authors. He said: "We found that genetic diversity has been lost dramatically compared to the Raj tigers and what diversity remains has become much more subdivided into the small (20-120 individual) populations that exist today.