JAKARTA, Indonesia » Five endangered Sumatran elephants have been found dead in Indonesia, and conservationists said Sunday that they suspect farmers poisoned the animals to stop them from damaging crops.

The elephants – four females and one male all under the age of 5 – were found dead late Friday in Riau province on Sumatra island, said Edi Susanto, a government conservationist.

Susanto suspects that owners of nearby palm oil plantations used cyanide to poison the animals, which are known for damaging crops. He said an investigation is under way and samples from the dead elephants have been sent for analysis.

"We have told the district heads in Riau province to ban farmers from tending crops in the woods where the elephants search for food," Susanto said.

Only 3,000 Sumatran elephants are believed to remain in the wild, a number that dwindles each year with poaching and killing by farmers angry over crop losses. The animals are prized by poachers for their ivory tusks.