Camera trap photo of a Sumatran tiger in the Leuser Ecosystem, Indonesia
Fiel et al. 2025, BKSDA, DLHK
A camera trap survey has identified more than double the number of critically endangered Sumatran tigers compared to studies found elsewhere on the Indonesian island, in a positive sign for protection efforts.
Sumatran tigers are the last remaining population of the subspecies Panthera tigris sondaicaone of two tiger subspecies according to recent taxonomic assessments.
Working with the indigenous Gayo people, researchers attached 60 sets of camera traps to trees in a previously unstudied part of the Leuser ecosystem in Sumatra, Indonesia, one of the largest intact rainforests in Southeast Asia.
The traps captured images of 17 tigers over a 90-day period in 2023 and 18 tigers in 2024, while previous 90-day surveys in Sumatra spotted only seven tigers on average. In total, the investigation identified 14 adult female tigers, 12 males and three pairs of cubs, as well as one adult tiger of unknown sex.
“It exceeded my expectations, simply because the literature up until this study said we weren’t supposed to find tigers in these densities,” says Joe Figel of the conservation organization Hutan Harimau. “It is therefore a very promising result, which demonstrates the many efforts made in this region.”
Sumatran tigers are threatened by poaching for trophies and traditional Chinese medicine, as well as logging for dipterocarps, a valuable hardwood. Due to limited data, the population estimate ranges from 173 to 883.
Although the 90-day periods were used for comparison, the researchers ultimately studied for 180 days in 2023 and 2024, which provides a more reliable record from one season to the next, says Deborah Martyr of the NGO Flora and Fauna International, who was not involved in the study.
A mother grooming a large male bear cub, which was spotted successfully living alone eight months later.
Fiel et al. 2025, BKSDA, DLHK
The higher-than-expected number of tigers in the Leuser ecosystem shows that the lowland forests there are rich in prey, especially sambar deer, Figel says. It also suggests that monthly rounds by rangers have deterred poaching.
Near Gunung Leuser National Park, the study area is patrolled by forest rangers paid by the NGOs Forum Konservasi Leuser and Hutan Harimau, in partnership with the Environment and Forestry Department of the formerly war-torn Aceh region.
But research suggests more rangers are needed. In recent years, tigers have disappeared in Vietnam, Cambodia and Laos.
“What more do we need as a wake-up call? Figel said. “The Southeast Asian tiger is currently in a desperate situation. »
Topics:
