"These findings have long term implications for the oil palm industry and those working in conservation as we have to look at a larger landscape rather than concentrate only on forested areas," said Dr Marc Ancrenaz, the lead author of the findings published in Oryx, the international journal of conservation.
This study was carried out by research based non-governmental organisation, Hutan - Kinabatangan Orangutan Conservation Programme (KOCP) and the Sabah Wildlife Department.
It began in 2008 with aerial surveys, followed by years of ground surveys and interviews with oil palm workers to investigate why the population of orangutans in the forested areas in Kinabatangan was dropping.
"Where were these missing orangutans. We knew they could not have just disappeared from the small forested areas of lower Kinabatangan.
So we looked outside the forested areas and what we found, truly shocked us," said Ancrenaz who is also scientific director of Hutan-KOCP, in a statement.
Ancrenaz said the researchers found that orangutan nests within the oil palm landscape within small patches of trees, even single trees.
"The orangutans are not adapting to the oil palm and are using them to find other forested areas.
This means the palm oil industry now has a very important role to play to sustain the long term survival of the orangutan population living in Kinabatangan and other agricultural lands in Sabah."
The study also found the orangutans only used the oil palm plants to nest when they had no access to native trees and usually did not go too far inside with 90 percent detected within 100 metres of the forest edge, although it did find that some had roamed further inside.
"While travelling through the oil palm plantations, the orangutans will supplement their diet by eating ripe fruits collected from the oil palm plants.
However, everyone must understand that this does not mean that orangutans can survive in oil palm plantations, its like people surviving on a carrot or an olive diet only."
The study found that orangutans need a high level of diversity in their diet with over 300 species of plants being recorded as being consumed by orangutans.
"Since the orangutan is a protected species under Sabah law, oil palm plantations have a legal responsibility to protect and ensure their safe passage.
"It is illegal to kill, hurt or harass an orangutan," said Sabah Wildlife Department director Datuk Dr. Laurentius Ambu.
"As such, the oil palm landscape must be adapted to the needs of the orangutans if we want to secure its long term survival in Kinabatangan and to sustain tourism in the area.
"The land use planning needs to be modified in order to reconnect isolated patches of forest found in Lower Kinabatangan.
"If this is not achieved, then Sabahans have to face the real possibility that the orangutan population in Kinabatangan is ultimately going to keep dropping until they become extinct."
Ancrenaz said only the palm oil industry can ensure a functional connectivity between the currently isolated forest patches inhabited by the orangutans.
The study is entitled, "Of Pongo, palms and perceptions: A multi disciplinary assessment of Bornean orangutans Pongo pygmaeus in an oil palm context" by Marc Ancrenaz, Felicity Oram, Laurentius Ambu, Isabelle Lackman, Eddie Ahmad, Hamisah Elahan, Harjinder Kler, Nicola K. Abram and Erik Meijaard.