One of the rarest primates in the world, which was so elusive it was thought to have become extinct, was caught on camera for the first time, researchers said yesterday.

The Horton Plains slender loris had only been seen four times since 1937 and vanished between 1939 and 2002, leading scientists to believe the wide-eyed mammal had become extinct.

Researchers from the Zoological Society of London’s edge of existence programme, who spent more than 200 hours looking for signs of the nocturnal primate in the mountain forest of central Sri Lanka, said they were “thrilled” to have photographed it.

The picture of the endangered mammal shows an adult male Horton Plains slender loris, characterised by short limbs and long dense fur, sitting on a forest branch.

The sub-species of slender loris has shorter and sturdier fore and hind limbs than those of any other loris in either Sri Lanka or southern India, showing how the mammal has adapted to living in the cool montane – or highland – forest, the researchers said.

ZSL conservation biologist Craig Turner said: “We are thrilled to have captured the first ever photographs and prove its continued existence – especially after its 65-year disappearing act.

“This is the first time we have been able to conduct such a close examination of the Horton Plains slender loris.

“The discovery improves our knowledge of this species, but we need to focus our efforts on the conservation and restoration of the remaining montane forest where this species still exists.

“Currently this accounts for less than one per cent of the land area of Sri Lanka.”

Research leader Saman Gamage said: “Nearly 1,000 nocturnal surveys have been completed in 120 different forest areas looking for all loris species to assess their status, ecological needs and current threats.”