A rare Sumatran elephant, missing its tusks, has been found dead in western Indonesia.

The elephant was discovered in Riau province, in Kampar, close to Teso Nilo National Park.

"We do not know what the cause of death is, we are still investigating it," said Sumanto, one of the park rangers.

"The elephant population in this Teso Nilo National Park is in a critical condition. I hope the government will follow up on this."

Estimates suggest there are less than 2,800 Sumatran elephants alive in the wild, marking a 50 per cent drop in numbers since 1985.

Scientists say that if current trends continue, the animals could be extinct in the wild in less than 30 years.

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