Healthy Sumatran Tiger Population Discovered in Indonesian Forests
Although tigers have disappeared from much of their historic range across Asia, new research suggests that a stronghold of Critically Endangered Sumatran tigers may be thriving on the Indonesian island of Sumatra.
Scientists working alongside local forest rangers installed infrared camera traps in forests outside of national parks to study tiger numbers and movement. Their work, carried out with the support of the Aceh provincial government, captured nearly three times more tiger images than earlier surveys and allowed researchers to identify far more individual animals.
The findings were published in Frontiers in Conservation Science and suggest the region contains one of the healthiest remaining tiger populations on the island.
“We documented a robust tiger population — likely among the strongest in Sumatra,” said Dr. Joe Figel, a conservation biologist who works closely with Indonesian wildlife agencies. “It now falls on us to make sure these tigers are properly protected.”
A Stronghold in the Leuser Ecosystem
The study focused on the Leuser Ecosystem, a vast forested region in northern Sumatra that is about three times the size of Yellowstone National Park. It contains a mix of lowland, hill, and mountain forests, with around 44% classified as intact forest landscape.
Importantly, the area is heavily patrolled by rangers, which researchers believe has played a major role in the tigers’ survival.
While only 5–10% of tiger habitat remains worldwide, this forest appears to offer enough space, prey, and shelter for tigers to breed and raise cubs.
How the Study Was Conducted
Camera traps were installed in three survey periods:
- 34 cameras from March to May 2023
- 59 cameras from June to December 2023
- 74 cameras from May to November 2024
Across all these monitoring periods, the cameras captured 282 clear tiger images, allowing the researchers to identify individuals based on their unique stripe patterns.
In total, they identified:
- 14 females
- 12 males
- 1 tiger of unknown sex
Female tigers were photographed an average of 14 times, while males appeared about 16 times each, suggesting the animals were regularly moving through healthy territory.
Signs of a Thriving Population
Several indicators point to a healthy ecosystem:
- High numbers of female tigers, which suggests good breeding conditions
- Documentation of three separate litters of cubs in just a six-month period
- Two brothers that were first photographed as cubs and later recorded again as adults
These signs suggest the habitat can support multiple generations of tigers.
Important Forests, Fewer Resources
Although the study area lies near Gunung Leuser National Park, the research actually took place mostly in provincially protected forests managed by the Aceh government — areas that receive far less funding and support than national parks.
Despite that limitation, these forests produced stronger tiger results than many earlier studies conducted inside better-funded national parks.
Only a few past surveys in Sumatra had recorded more than 10 tigers in a single area. This new study documented 27 individuals, with density levels comparable only to highly protected zones in southern Sumatra.
Guidance for Future Conservation
Beyond population numbers, the study also provided valuable data about tiger movement patterns, which can help design better camera trap layouts and monitoring strategies in the future.
Researchers emphasized that this success is not accidental.
“These results are due to persistent habitat protection and strong prey populations,” Figel said.
“The work of government agencies, local Acehnese and Gayo communities, and conservation partners has been essential.”
A Fragile but Hopeful Future
The findings show that, with strong protection and local support, even critically endangered species like the Sumatran tiger can survive — and possibly recover.
But researchers stress that continued protection is essential if this rare population is to persist.