The Sumatran Tiger is a rare tiger subspecies and was classified as critically endangered by IUCN in 2008 as the population was estimated at 441 to 679 individuals, with no sub-population larger than 50 individuals and a declining trend. The Sumatran tiger is the only surviving member of the Sunda Islands group of tigers that included the now extinct Bali tiger and Javan tiger.
The Sumatran tiger is described on the basis of several skull, pelage and striping features in which it is distinct from the Indian and Javan tigers. It is darker in fur color and has thicker stripes than the Javan tiger. Stripes tend to disintegrate into spots near their ends, and lines of small dark specks between regular stripes may be found on the back, flanks and hind legs. Males have a prominent ruff, which is especially marked in the Sumatran tiger. The Sumatran tiger is one of the smallest tiger subspecies. Males weigh 100 to 140 kg (220 to 310 lb) and measure 220 to 225 cm (87 to 89 in) in length between the pegs with a greatest length of skull of 295 to 335 mm (11.6 to 13.2 in). Females weigh 75 to 110 kg (165 to 243 lb) and measure 215 to 230 cm (85 to 91 in) in length between the pegs with a greatest length of skull of 263 to 294 mm (10.4 to 11.6 in).
Sumatran tigers persist in isolated populations across Sumatra. They occupy a wide array of habitats, ranging from 0 m above sea level in the coastal lowland forest of Bukit Barisan Selatan National Park on the southeastern tip of Lampung Province to 3,200 m (10,500 ft) in mountain forests of Gunung Leuser National Park in Aceh Province.
They prefer forest with dense understory cover and steep slope, and they strongly avoid forest areas with high human influence in the forms of encroachment and settlement. In acacia plantations they tend to use areas closer to water, and prefer areas with older plants, more leaf litter and thicker sub-canopy cover. They avoid areas with high human activity.
The Sumatran tiger diet consists of Great Argus Pheasant, Pigtail Macaque, porcupine, Malay tapir, wild pig, Greater and Lesser mouse-deer, muntjac, and Sambar deer.