In the remote jungles of Borneo, near Indonesia's border with Malaysia, scientists have discovered a large population of orangutans, possibly more than 2,000, lifting hopes for the survival of the species.

A survey team acting on local rumors traveled into the heart of a two-million-acre forest - to the Sangkuilirang mountains of Indonesia's eastern Kalimantan province. There they counted 219 orangutan nests in a jungle isolated by jagged, limestone cliffs.

The extent of the find, along a 10-kilometer tract of land, surpassed everyone's expectations.

Erik Meijaard, a senior ecologist with the U.S.-based Nature Conservancy, helped make the find.

"The significance of this is that pretty much all the news that comes out of orangutan conservation is normally negative, and this, for a change, is positive news," he explained. "It's a population of at least a couple of hundred, probably a couple of thousand, a couple of thousand animals that are new, that are new to science at least."

This is a rare boost for the great ape. Orangutan numbers have plummeted in recent decades, as logging has felled rainforests where they live and palm oil plantations have spread across their habitat.

The word orangutan is Malay and translates as person of the jungle. They are known for their intelligence and their reddish-brown hair, which distinguishes them from their cousins in Africa.

Orangutans are only found on Borneo and Sumatra although fossils have been found in Java, the Thai-Malay peninsula, Vietnam and in China.

Meijaard says the recent discovery has raised hopes that their numbers could be greater than previously thought, particularly in Indonesia Borneo where large tracts of forests have yet to be mapped.

"We are going to go back in and get a better understanding of how far this population actually ranges and once we've done this we'll get a better understanding of the numbers," he said.

He says the next steps are to work with local governments to protect these habitats and prevent any further declines in orangutan numbers.