The primates were found dead Monday by workers at the Shangri-La Rasa Ria Resort who suspected something amiss when they did not appear during feeding time in the morning, the New Straits Times said.

The three were among six orang-utans, an endangered species, under rehabilitation at the resort's nature reserve, the daily said.

The carcasses have been sent to the Sepilok Orang-utan Sanctuary north of Sabah state on Borneo island for post-mortems. No other details were available.

The huge Borneo and Indonesia's Sumatra islands are the world's only homes of the orang-utan, whose survival has been threatened by land development, forest fires, poaching and illegal hunting.

Scientists estimate some 15,000 to 20,000 orang-utans still survive in Borneo and about 10,000 more in Sumatra but experts warned the large red apes could be extinct within a decade due to rapid depletion of primary forests.

TERRA.WIRE