In Vietnam, Laos, and Cambodia conservationists estimate hunting and poaching have reduced tiger numbers to fewer than 30 in each country.

In eastern Cambodia's Mondulkiri Protected Forest, conservationists have brought in unique specialists to track down the few remaining tigers.

Sadie May and Scooby Doo are black Labrador retrievers. They are part of Conservation Canines, a project at the University of Washington in the U.S. that trains dogs to sniff for wild animal feces - also called scat.

Scooby's handler, Jennifer Hartman, says the dogs are much faster than human researchers at finding tiger scat.

"And we train them to sit at them, which shows us that they have something," she said.  "And, we come and check it out. And, all of our dogs are extremely ball driven - they love to play. So, their reward for finding a scat is they get to play ball for two to three minutes and that keeps them good all day long."

The handlers note where the scat is found and take a sample for analysis to determine if it is from a tiger and to check the animal's health.

Sadie's handler, Elizabeth Seely, says they can learn a lot from animal droppings.

"We can get hormone levels, physiological data, disease status," she said. "And, all of it combined will give us an overall population health."

Cambodia's Mondulkiri Forest was once rich in wildlife, including tigers, but hunting and poaching largely emptied the region and killed off almost all the tigers.

Lean Kha was a soldier with the communist Khmer Rouge in the early 1980s and admits he killed wildlife for food and trade, including 14 tigers.

He says he became a forest ranger to make up for what he calls his past sins.

"There were a lot of animals when I was with the Khmer Rouge and less afterwards," he said. "But, since I became an animal protector it seems like wildlife numbers are increasing."

Conservation Canines has teamed up with Cambodian rangers and the conservation group WWF to protect wild tigers. The big cats once roamed throughout Asia, into Siberia, but conservationists say only a few thousand tigers remain in the wild; far more live in captivity. Without immediate action, the WWF says, by 2022, there may no longer be any wild tigers.

Nick Cox, the WWF's Dry Forest and Tiger Program coordinator for the countries along Southeast Asia's Mekong River, says the forests of Cambodia's eastern plains offer an intact habitat for reviving wild tigers.

"These are some of the largest protected areas in this part of Asia and particularly important for conservation because they hold huge potential for recovering wildlife populations including tiger," he said.

The WWF has set up cameras in parts of the forest to capture images of elusive wildlife.

But the last photo they got of a tiger was in 2007.

Conservationists hope that Sadie May and Scooby Doo will find some fresher evidence of wild tigers - and help efforts to save them.