The Sumatran tiger is a group of tigers known as Panthera tigris sondaica that live on the island of Sumatra in Indonesia. These tigers are the only remaining tiger population in the Sunda Islands because the Bali and Javan tiger populations disappeared during the 20th century.

Studies of DNA from the complete mitochondrial genes of 34 tigers show that Sumatran tigers are clearly different from other tiger subspecies found on the mainland. In 2017, a group of experts called the Cat Classification Task Force updated the scientific classification of cats and confirmed that living and extinct tiger populations in Indonesia are classified as P. t. sondaica.

Taxonomy

In 1844, Coenraad Jacob Temminck gave the scientific name Felis tigris sondaicus to a tiger specimen found on the island of Java.

In 1929, Reginald Innes Pocock introduced the name Panthera tigris sumatrae for a tiger specimen from Sumatra, based on a skin and a skull. The skulls and coat patterns of tigers from Java and Sumatra are very similar. Because of this, P. t. sondaica is now considered the correct name for both living and extinct tiger populations in Indonesia.

Evolution

DNA analysis supports the idea that Sumatran tigers became separated from other tiger groups when sea levels rose during the transition from the Pleistocene to the Holocene era, about 12,000–6,000 years ago. This separation is shown by the Sumatran tiger’s genetic differences from all living mainland tigers, which form a group closely related to one another. Evidence of this isolation includes specific DNA markers, such as two unique mitochondrial DNA spots, 10 mitochondrial DNA patterns, and 11 unique microsatellite markers out of 108 total. The Sumatran tiger’s high genetic diversity and distinct evolutionary history suggest that gene exchange between island and mainland tiger populations was very limited.

Characteristics

The Sumatran tiger was identified using two animal samples that had different skull sizes and stripe patterns compared to Bengal and Javan tiger samples. It has darker fur and broader stripes than the Javan tiger. The stripes often fade into spots near their ends, and small, dark spots appear between the regular stripes on the back, sides, and hind legs. The Sumatran tiger has more stripes than other tiger subspecies. Male Sumatran tigers have a noticeable ruff of fur, which is especially visible in this subspecies.

The Sumatran tiger is one of the smallest tiger subspecies. Male tigers measure between 2.2 to 2.55 meters (7 feet 3 inches to 8 feet 4 inches) from nose to tail, have skull lengths of 295 to 335 millimeters (11.6 to 13.2 inches), and weigh between 100 to 140 kilograms (220 to 310 pounds). Female tigers weigh between 75 to 110 kilograms (165 to 243 pounds) and measure 2.15 to 2.30 meters (7 feet 1 inch to 7 feet 7 inches) from nose to tail, with skull lengths of 263 to 294 millimeters (10.4 to 11.6 inches).

A near telomere-to-telomere chromosome-level genome assembly of the Sumatran tiger was published in 2026. This assembly is approximately 2.46 gigabases in size, covers 19 chromosomes, has a BUSCO completeness of 95.3%, and includes predictions of 23,737 complete genes.

Distribution and habitat

The Sumatran tiger lives in small and separate groups across Sumatra. These groups are found from the lowland forests near the coast in Bukit Barisan Selatan National Park, located in the southeastern part of Lampung Province, up to mountain forests at 3,200 meters (10,500 feet) in Gunung Leuser National Park in Aceh Province. These tigers live in 27 areas larger than 250 square kilometers (97 square miles), which together cover 140,226 square kilometers (54,142 square miles). About one-third of these areas are within protected lands.

Sumatran tigers mostly live in lowland and hill forests, where up to three tigers may be found in an area of 100 square kilometers (39 square miles). They also use non-forest areas and lands near human settlements, but less often.

In 1978, scientists estimated there were about 1,000 Sumatran tigers based on survey responses. By 1985, 26 protected areas across Sumatra were identified as home to around 800 tigers. In 1992, it was estimated that 400–500 tigers lived in five national parks and two protected areas. At that time, the largest group of tigers, with 110–180 individuals, was found in Gunung Leuser National Park. By 2011, Kerinci Seblat National Park in central Sumatra had the highest number of tigers, with 165–190 individuals. This park also had the highest tiger presence rate among Sumatra’s protected areas, with 83% of the park showing signs of tigers.

In 2017, the total Sumatran tiger population was estimated at 618 ± 290 individuals.

Ecology and behaviour

Sumatran tigers prefer forests that are not farmed and rarely use areas with acacia or oil palm plantations, even when these are available. In natural forests, they often choose areas with higher ground, less rain each year, farther from the forest edge, and closer to the center of the forest. They like forests with thick plant cover near the ground and steep slopes, and they avoid areas where humans live or work, such as places where people settle or cut into the forest. In acacia plantations, they tend to stay near water sources and prefer areas with older trees, more fallen leaves, and denser cover under the tree canopy. Few tigers are found in oil palm or rubber plantations. Having enough plants covering the ground is essential for tigers, no matter where they live. Without enough cover, tigers are more likely to be harmed by humans. Factors related to human activity, such as people living near forests, cutting trees, or working in acacia plantations, reduce the number of tigers in an area. Studies using camera traps in southern Riau found very few prey animals and low tiger numbers in peat swamp forests. In the newly created Tesso Nilo National Park, repeated checks showed more tigers over time, from 0.90 tigers per 100 km (39 sq mi) in 2005 to 1.70 tigers per 100 km (39 sq mi) in 2008.

In Bukit Barisan Selatan National Park, nine prey species weighing more than 1 kg (2.2 lb) were identified, including the great argus, pig-tailed macaque, Malayan porcupine, Malayan tapir, banded pig, greater and lesser mouse-deer, Indian muntjac, and Sambar deer.

Threats

Major threats to Sumatran tigers include habitat loss caused by the expansion of palm oil and acacia plantations, a decrease in prey animals, and illegal trade for the domestic market. Conflicts with humans also pose a significant threat. Poachers use wire snares to trap tigers, and tigers are sometimes accidentally caught in traps set by deer hunters or farmers trying to protect crops from wild boar.

Tigers require large, connected forest areas to survive. Between 1985 and 1999, forest loss in Bukit Barisan Selatan National Park averaged 2% per year. A total of 661 km² (255 sq mi) of forest disappeared inside the park, and 318 km² (123 sq mi) were lost in a 10-km buffer zone outside the park. Lowland forests and forests on gentle slopes disappeared faster than montane forests or those on steep slopes. Most forest loss was due to agricultural development, leading to predictions that by 2010, 70% of the park would be converted to farmland. Camera-trap data showed tigers avoiding forest edges. Based on mammal distribution, core tiger habitat was expected to be reduced to 20% of the remaining forest by 2010.

Kerinci Seblat National Park, home to Sumatra’s largest tiger population, faces high deforestation rates in its outer areas. This is driven by unsustainable demand for natural resources due to rapid human population growth in Indonesia and government efforts to expand tree-crop plantations and commercial logging, which often cause forest fires. Many tigers were relocated to the park’s center for conservation, but lowland hill forests on the outskirts remain vulnerable to logging, which contributes to declining tiger numbers.

The expansion of plantations increases greenhouse gas emissions, contributing to human-caused climate change and adding pressure on endangered species. As tigers move northward due to climate changes, conflicts with humans may increase. Between 1987 and 1997, Sumatran tigers were reported to have killed 146 people and at least 870 livestock. In West Sumatra, Riau, and Aceh, 128 incidents were recorded, with 265 tigers killed and 97 captured in response. From 1998 to 2002, 35 more tigers were killed. From 2007 to 2010, tigers killed 9 people and 25 additional tigers were killed.

In 1997, an estimated 53 tigers were killed by poachers, and their parts were sold across northern Sumatra. Actual numbers for all of Sumatra are likely higher. Farmers killed tigers to protect livestock and sold them to shops, pharmacies, and markets. In 2006, tiger parts such as skins, bones, and canines were found in 33 of 326 retail outlets surveyed in 28 cities and nine seaports across seven provinces. Tiger bones had the highest average price at US$116 per kg. Evidence suggests tiger parts are smuggled out of Indonesia. In July 2005, over 140 kg (310 lb) of tiger bones and 24 skulls were seized in Taiwan from a shipment in Jakarta.

Between 2013 and 2014, Kerinci Seblat National Park saw a rise in poaching, with the highest number of snare traps removed during a patrol effort similar to previous years. It is unclear if conservation strategies are reducing poaching, despite millions of dollars spent annually on protection efforts. In Aceh province, insufficient or nonexistent ranger patrols in provincially-managed forests leave tigers vulnerable to poaching. Between January 2020 and June 2025, 127 tigers were confiscated in 77 seizures across Indonesia.

Conservation

Panthera tigris is listed on CITES Appendix I. Hunting is not allowed in Indonesia.

In 1994, the Indonesian Sumatran Tiger Conservation Strategy was created to help protect tigers in Sumatra from a possible crisis. The Sumatran Tiger Project (STP) began in June 1995 near Way Kambas National Park. Its goal was to ensure that wild Sumatran tigers could survive for many years and to collect important information about their lives to help manage their populations. By August 1999, STP teams studied 52 areas in Lampung Province that could be tiger habitats. Only 15 of these areas were still healthy enough to support tigers. A program was started to understand how tigers and humans interact in the park, so that conservation groups could use facts instead of guesses to solve conflicts.

In 2007, Indonesia’s Forestry Ministry and Safari Park partnered with the Australia Zoo to protect Sumatran tigers and other endangered species. This program includes saving tigers in the wild, reducing conflicts between tigers and people, and helping tigers recover and return to their natural homes. Conservation efforts in Indonesia have increased political support for protecting wildlife and biodiversity. In 2009, Indonesia’s president promised to greatly reduce deforestation and create plans at national, provincial, and local levels that protect the environment.

Between 2005 and 2015, about $210 million was spent on tiger protection efforts, including helping forest rangers patrol areas and stopping illegal hunting. These activities were part of the Global Tiger Recovery Plan, which aimed to double the number of wild tigers by 2020. In November 2016, Batu Nanggar Sanctuary was opened in North Padang Lawas Regency, North Sumatra, to help protect Sumatran wildlife.

A survey of 600 people showed that most were willing to pay more for products that support Sumatran tiger conservation.

As of 2013, about 375 Sumatran tigers were recorded in a global list and management plan, with 50 of them living in 14 zoos in Australia and New Zealand. All of these tigers were descendants of 15 original tigers. Fourteen cubs had health issues, such as balance problems, eye movement problems, and head tilting, which improved by the time they were two years old. These problems were likely caused by close family relationships and inbreeding.