A camera trap survey has identified more than double the number of critically endangered Sumatran tigers than studies have 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 sondaica, one of two tiger subspecies according to

Working with the Gayo Indigenous 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 South-East 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 on Sumatra spotted only seven tigers on average. In total, the survey identified 14 adult female tigers, 12 males and three sets of cubs, as well as one adult tiger of unknown sex.

“It surpassed my expectations, just because the literature up until this study said that we weren’t supposed to find tigers in these densities,” says at the conservation organisation Hutan Harimau. “So it was a very promising result, testament to a lot of efforts that have been going on in that region.”

Sumatran tigers are threatened by poaching for trophies and traditional Chinese medicine, as well as logging for dipterocarp trees, a valuable hardwood. Because of limited data, the population estimate varies from 173 to 883.

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While the 90-day periods were used for comparison, the researchers ultimately surveyed for 180 days in both 2023 and 2024, which provides a more reliable record across seasons, says Deborah Martyr at the NGO Flora and Fauna International, who was not involved in the study.

The higher-than-expected tiger count in the Leuser ecosystem shows the lowland forests there are rich in prey, especially sambar deer, says Figel. It also suggests monthly rounds made by rangers have deterred poaching.

Near Gunung Leuser National Park, the study area is patrolled by rangers paid by the NGOs Forum Konservasi Leuser and Hutan Harimau, in partnership with the Environment and Forestry Service of the previously war-torn Aceh region.

But research suggests more rangers are necessary. In recent years, tigers have gone extinct in Vietnam, Cambodia and Laos.

“What more of a wake-up call do we need?” says Figel. “The tiger in South-East Asia right now is really in dire straits.”

These photos tell an unusual rescue story – the release of Javan slow lorises into Ujung Kulon National Park on Java Island, Indonesia, last month.

Photojournalist Garry Lotulung joined a team from the Indonesian branch of International Animal Rescue, the non-profit Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI), as they released Javan slow lorises, transporting the animals on their backs (pictured below).

The Javan slow loris (Nycticebus javanicus) is , as a result of the destruction of its rainforest habitat and its capture for sale as pets or for body parts in traditional medicine. These animals often have their teeth removed to stop them from biting, which means they can’t feed in the wild. But if the rescued animals can look after themselves, YIARI releases them into the wild.

Slow lorises look cute – but they are the world’s . When threatened, they raise their arms above their head and take a secretion from glands on their arms into their mouths. The secretion forms venom when combined with saliva.

This two-step system is unique to slow lorises. While the nature of the venom isn’t fully understood, their bites are painful, slow to heal and can cause allergic reactions. Spread on their fur, the venom may also protect the animals from parasites such as ticks and fleas.

These animals were given vitamins (main picture) and then placed in an enclosure for monitoring (pictured above). “They are monitored for several days to two weeks to ensure they can survive in the wild before being permanently released,” says Lotulung.