Indian wildlife experts believe they have discovered a new natural habitat of the endangered Royal Bengal tiger in the country's north-eastern region.

Wildlife researchers combing the Trishna reserve forest in Tripura for a bison census recently came across one tigress and two cubs. Tigers have not been seen in this forest since 1976.

The news has galvanised tiger enthusiasts and conservationists who are now examining various theories about how tigers could have existed without anybody knowing about it for so long.

One possibility that officials from Wildlife Institute of India in Dehradun are examining is whether the tigers could have "infiltrated" from forests in Nepal or Bhutan that are known to have tigers.

According to Project Tiger officials, the institute's Asish Kumar, who was conducting the bison census in Tripura, had seen the tigress and her cubs on several occasions and had taken their pugmarks.

An initial analysis of the pugmarks showed that the tigress belonged to the Royal Bengal variety.

Wildlife officials were preparing to carry out more researches into their new discovery that has come as good news for India, which has come under fire from conservationists for the dwindling tiger population.