Sumatran tiger encounters nearly triple in camera trap photos, study finds

A focused survey in northern Sumatra is offering fresh hope for one of the world’s most imperiled big cats. Using infrared camera traps across provincial forests in Aceh, researchers have captured a surge in Sumatran tiger detections—providing new evidence that well-protected, connected forest patches can support healthy tiger populations even outside national parks.

The multi-season effort combined local rangers’ knowledge with systematic camera placement to map tiger numbers, sexes, and movement patterns. The volume and quality of the photographic data surprised the team and point to practical ways to improve monitoring and protection across Sumatra.

How the camera-trap effort was organized in Aceh

Researchers partnered with community members and provincial authorities to deploy infrared cameras across northern stretches of the Leuser ecosystem. The monitoring took place over three distinct periods, with camera coverage increasing as the project scaled up:

• March–May 2023: 34 cameras installed
• June–December 2023: 59 cameras active
• May–November 2024: 74 cameras active

This stepped approach allowed the team to expand spatial coverage and test how camera density affected detection rates. Teams prioritized areas of intact forest and known wildlife corridors, relying on ranger patrols to maintain the devices and reduce disturbance.

What the photos revealed about Sumatran tiger numbers and behavior

Across the three monitoring windows, the cameras captured 282 images clear enough to identify individual tigers. By matching unique stripe patterns, researchers identified 27 distinct individuals: 14 females, 12 males, and one tiger whose sex could not be determined.

• Average detections per individual: females ~14 photos, males ~16 photos.
• Evidence of reproduction: three separate litters were documented during a six-month session in 2023.
• Observed juvenile development: at least two male siblings photographed together as cubs were later recorded solo as adults.

High numbers of adult females and repeated sightings of the same individuals suggest stable prey availability and suitable denning areas—conditions necessary for females to raise multiple litters over time.

Why the Leuser landscape still supports tigers

The Leuser ecosystem stands out on Sumatra for several reasons. At roughly three times the size of Yellowstone National Park, it is the largest continuous block of tiger habitat left on the island, featuring a mosaic of lowland, hill, and montane forests. Nearly half of these areas remain as intact forest landscape, and the region benefits from especially active ranger patrols.

Local stewardship played a major role. Community engagement, provincial government protection, and donor support helped preserve tracts of lowland and hill forest where tiger prey is abundant. Although provincial forests do not receive the same resources as national parks like Gunung Leuser National Park—which lies within the broader ecosystem—dedicated conservation actions have kept critical habitat functioning.

How these results compare to past surveys and what they mean

The Aceh camera-trap program recorded almost three times as many tiger images as comparable 90-day surveys previously conducted at other Sumatran sites. It also yielded more identifiable individuals than most earlier studies in the region. Only a few past surveys—conducted inside better-funded national parks—reported more than 10 tigers in a single campaign, and higher density estimates than those found here were only observed in an intensive protection zone in southern Sumatra.

These contrasts underline a key point: protection on the ground, rather than formal park designation alone, drives tiger persistence.

Practical takeaways for future monitoring

• Camera spacing and placement: Movement data from this study can inform optimal trap spacing and survey duration.
• Value of multi-season sampling: Repeated monitoring increases detection of resident individuals and litters.
• Community and government collaboration: Local patrols and stakeholder buy-in improve camera maintenance and reduce poaching risk.

Conservation implications and ongoing responsibilities

Researchers emphasize that the findings are not an endpoint but a call to action. The presence of a robust, breeding population in provincially protected forests shows that tigers can thrive where habitat and prey are maintained and enforcement is consistent. Continued investment—both financial and institutional—will be required to sustain these gains.

The study, published in Frontiers in Conservation Science, supplies managers with actionable data on tiger movement and density that can refine monitoring protocols across Sumatra and help prioritize protection where it matters most.

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Michael Thompson

Michael Thompson is an experienced journalist covering U.S. and global news. With ten years on the front lines, he breaks down political and economic stories that matter. His precise writing and keen attention to detail help you grasp the real‑world impact of every event.