By Ella Davies
Earth News reporter
Greater bamboo lemurs in Madagascar are a step further from extinction.
Fewer than 300 of the lemur, the world's rarest, were thought to remain.
But by following up reports from local people, conservationists have found new "lost" populations of the lemur, which extends the primate's range to twice that previously thought.
Researchers are now working with local communities to monitor and protect the rainforest-dwelling species from hunting and habitat destruction.
Like many of Madagascar's unique species, the greater bamboo lemur (Prolemur simus) is endemic to the island.
As their name suggests, the lemurs feed primarily on bamboo. But this dependence on a single food-source makes them vulnerable to changes in their environment.
Variously described as "the world's rarest lemur species" and "one of the top 25 most endangered primates", the IUCN reports that fewer than 250 mature individuals exist.
Researchers from conservation charity Association Mitsinjo partnered with the Aspinall Foundation, Madagascan primate study group GERP and Conservation International Madagascar to learn more about the current state of the animals.
Greater bamboo lemurs are named for their diet
The team's initial search took place in the Ankeniheny-Zahamena Corridor, a major part of Madagascar's remaining rainforest that runs along its eastern coast.
Dr Rainer Dolch coordinated the first population surveys in 2007.
"[The lemurs] were thought to be confined to southeastern Madagascar until we discovered a new population in the Torotorofotsy wetlands, the first individuals of the species to be discovered north of the Mangoro River [for] 130 years," he said.
The team returned last year to investigate isolated sites on the fringes of the corridor after collecting local people's reports of both lemurs and their favoured bamboo habitat.
The conservationists' efforts were rewarded with confirmed sightings of 65 individuals and evidence of the lemurs' existence in more than double the number of sites that were previously known to occur.
The populations found extend the species' known range 85 km further north than previously recorded.
The researchers' findings are published in the American Journal of Primatology.
Dr Dolch attributed the discoveries to the help of the local people, he said: "They had a crucial role in the discovery of the species and they will play a crucial role in its conservation."
Threats facing greater bamboo lemurs include hunting pressures and the fragmentation, disturbance and destruction of their habitat.
Human activities including mining and timber felling are of major concern.
Conservationists hope that positive actions by local people will provide the lemurs with a brighter future.
"We are closely working with local communities for the monitoring of the species and the protection of their habitat," said Dr Dolch.
Dr Dolch's work to replant trees and link fragmented areas of rainforest features in the BBC Two documentary "Attenborough and the Giant Egg".
In the programme naturalist David Attenborough returns to Madagascar 50 years after he first filmed there.
Attenborough and the Giant Egg broadcasts on BBC TWO at 2000 GMT on Wednesday, March 2.