Conservationists plan expedition to secret ‘Noah’s Ark’ in Sumatra

After photographing tigers and tapirs in one of Sumatra's least known wildernesses, an unlikely pair of conservationists are hoping to discover a hidden population of orangutans in high altitude forests - and who knows what else.

Just a few years ago this place had no name. And in fact its new moniker - Hadabaun Hills - is the sole creation of Indonesian conservationist Haray Sam Munthe. Hadabaun means "fall" in the local language - Munthe suffered a terrible one in these hills while looking for tigers in 2013. But Hadabaun or Fall Hills remains unrecognised by the Indonesian governments and is a blank spot on the world's maps - though it may be one of the last great refuges for big mammals on the island of Sumatra.

Last year a ragtag, independent group of local and international conservationists, led by Munthe and Greg McCann of Habitat ID, used camera traps to confirm Sumatran tigers and Malayan tapirs in these hills. Next month they hope to uncover a lost population of Sumatran orangutans.