Before the deadly landslides and floods hit Indonesia about two weeks ago, Amran Siagian, 39, frequently met Tapanuli orangutans on a hill in the region of Sipirok, North Sumatra province.

Siagian, who has been working as a ranger to protect the endangered animal at the Orangutan Information Center (OIC) for at least five years, remembers how the orangutans were fond of eating durian and other fruits from farms in the area.

But after the landslides hit Sipirok, the orangutans are nowhere to be seen.

The cyclone-induced floods and landslides have killed 962 people as of Tuesday, with 291 listed as missing. The storms also killed about 200 people in southern Thailand and Malaysia.

"They must have moved away, further and further away. I could no longer hear their voices," Siagian told Reuters.

Local leaders and green groups said deforestation linked to mining and logging aggravated the impact of the floods and landslides.

In Sipirok, a village in the region of South Tapanuli which was among the hardest hit by the disaster, large trees appear to have been cut down. Siagian said a company had been logging in the area for at least a year.

The deforestation had affected the orangutans even before the floods, he said.

"The orangutans live by moving between forest canopy, from branch to branch. If the forest is sparse, it must be difficult for them," Siagian said.

OIC founder Panud Hadisiswoyo said there were about 760 orangutans living in Tapanuli region.

"The major threat is the loss of forest due to plantations and extractive industry," he said.

In total, around 119,000 orangutans live in Indonesia and Malaysia, according to World Wildlife Fund.

"If there is no government help, the orangutans could go extinct here. Especially with this massive deforestation," Siagian said.

-Ahmad Luqman Ismail and Aidil Ichlas