The Sumatran tiger is a rare tiger subspecies that inhabits the Indonesian island of Sumatra.
It was classified as critically endangered by IUCN in 2008 as the population was estimated
at 441 to 679 individuals, with no subpopulation 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. Sequences from complete mitochondrial genes of 34 tigers support the hypothesis
that Sumatran tigers are diagnostically distinct from mainland populations.
Characteristics
Pocock first described the Sumatran tiger 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 colour 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. The frequency of stripes is higher than in other
subspecies. 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 and measure 2.2 to 2.25 m in length between
the pegs with a greatest length of skull of 295 to 335 mm. Females weigh 75 to 110 kg
and measure 215 to 230 cm in length between the pegs with a greatest length of skull of
263 to 294 mm. Distribution and habitat
Sumatran tigers persist in isolated populations across Sumatra. They occupy a wide array of
habitats, ranging from sea level in the coastal lowland forest of Bukit Barisan Selatan National
Park on the southeastern tip of Lampung Province to 3,200 m in mountain forests of Gunung
Leuser National Park in Aceh Province. They have been repeatedly photographed at 2,600 m
in a rugged region of northern Sumatra, and are present in 27 habitat patches larger than
250 km2. In 1978, the Sumatran tiger population was
estimated at 1,000 individuals, based on responses to a questionnaire survey. In 1985, a total
of 26 protected areas across Sumatra containing approximately 800 tigers were identified.
In 1992, it was estimated that 400–500 tigers lived in five national parks and 2 protected
areas. At the time, the largest population was reported from the Gunung Leuser National
Park as comprising 110 to 180 individuals. However, a more recent study shows that the
Kerinci Seblat National Park in central Sumatra has the highest population of tigers on the
island, estimated to be at 165–190 individuals. The park also was shown to have the highest
tiger occupancy rate of the protected areas, with 83% of the park showing signs of tigers.
In fact, there are more tigers in the Kerinci Seblat National Park than in all of Nepal,
and more than in China, Laos, Cambodia and Vietnam combined.
Ecology and behaviour Sumatran tigers strongly prefer forest and
use plantations of acacia and oil palm far less than their availability. Within natural
forest areas they tend to use areas with higher elevation, lower annual rainfall, farther
from forest edge, and closer to forest centres. 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. Tiger records in oil palm plantations and
in rubber plantations are scarce. The availability of adequate vegetation cover at the ground
level serves as an environmental condition fundamentally needed by tigers regardless
of the location. Without adequate understory cover, tigers are even more vulnerable to
persecution by humans. Human disturbance related variables negatively affect tiger occupancy
and habitat use. Variables with strong impacts include settlement and encroachment within
forest areas, logging and the intensity of maintenance in acacia plantations. Camera
trapping surveys conducted in southern Riau revealed an extremely low abundance of potential
prey and a low tiger density in peat swamp forest areas. Repeated sampling in the newly
established Tesso Nilo National Park documented a trend of increasing tiger density from 0.90
individuals per 100 km2 in 2005 to 1.70 individuals per 100 km2 in 2008.
In the Bukit Barisan Selatan National Park, nine prey species larger than 1 kg of body
weight were identified including Great Argus Pheasant, Pigtail Macaque, porcupine, Malay
tapir, wild pig, Greater and Lesser mouse-deer, muntjac and Sambar deer.
Threats Major threats include habitat loss due to
expansion of palm oil plantations and planting of acacia plantations, prey-base depletion,
and illegal trade primarily for the domestic market.
Tigers need large contiguous forest blocks to thrive. Between 1985 and 1999, forest loss
within Bukit Barisan Selatan National Park averaged 2% per year. A total of 661 km2
of forest disappeared inside the park, and 318 km2 were lost in a 10-km buffer, eliminating
forest outside the park. Lowland forest disappeared faster than montane forest, and forests on
gentle slopes disappeared faster than forests on steep slopes. Most forest conversion resulted
from agricultural development, leading to predictions that by 2010 70% of the park will
be in agriculture. Camera-trap data indicated avoidance of forest boundaries by tigers.
Classification of forest into core and peripheral forest based on mammal distribution suggests
that by 2010, core forest area for tigers will be fragmented and reduced to 20% of remaining
forest. Despite being given full protection in Indonesia
and internationally, tiger parts are still found openly in trade in Sumatra. In 2006,
surveys were conducted over a seven month period in 28 cities in seven Sumatran provinces
and nine seaports. A total of 326 retail outlets were surveyed, and 33 were found to have tiger
parts for sale, including skins, canines, bones and whiskers. Tiger bones demanded the
highest average price of US$ 116 per kg, followed by canines. There is evidence that tiger parts
are smuggled out of Indonesia. In July 2005, over 140 kg of tiger bones and 24 skulls
were confiscated in Taiwan in a shipment from Jakarta.
Conservation Panthera tigris is listed on CITES Appendix
I. Hunting is prohibited in Indonesia. In 1994, the Indonesian Sumatran Tiger Conservation
Strategy addressed the potential crisis that tigers faced in Sumatra. The Sumatran Tiger
Project was initiated in June 1995 in and around the Way Kambas National Park in order
to ensure the long-term viability of wild Sumatran tigers and to accumulate data on
tiger life-history characteristics vital for the management of wild populations. By August
1999, the teams of the STP had evaluated 52 sites of potential tiger habitat in Lampung
Province, of which only 15 these were intact enough to contain tigers. In the framework
of the STP a community-based conservation programme was initiated to document the tiger-human
dimension in the park in order to enable conservation authorities to resolve tiger-human conflicts
based on a comprehensive database rather than anecdotes and opinions.
In 2007, the Indonesian Forestry Ministry and Safari Park established cooperation with
the Australia Zoo for the conservation of Sumatran tigers and other endangered species.
The program includes conserving Sumatran tigers and other endangered species in the wild,
efforts to reduce conflicts between tigers and humans, and rehabilitating Sumatran Tigers
and reintroducing them to their natural habitat. One hectare of 186 hectares of Taman Safari
is the world's only Sumatran tiger captive breeding center which has also sperm bank.
An 110,000 acre conservation area and rehabilitation center, Tambling Wildlife Nature Conservation,
has been set up on the edge of a national park on the southern tip of Sumatra. On October
26, 2011, a tigress who had been captured with an injured leg in early October delivered
three male cubs in a temporary cage, while waiting for release after her recovery.
On Feb 3, 2014 three Sumatran tiger cubs were born to a five year old tigress in London
Zoo, in the Zoo's Tiger Territory; a £3.6m project to encourage endangered subspecies
of tiger to breed. Evolution
Analysis of DNA is consistent with the hypothesis that Sumatran tigers have been isolated from
other tiger populations after a rise in sea level that occurred at the Pleistocene to
Holocene border about 12,000–6,000 years ago. In agreement with this evolutionary history,
the Sumatran tiger is genetically isolated from all living mainland tigers, which form
a distinct group closely related to each other. See also
Bali tiger Javan tiger
Trinil tiger References
External links The Sumatran Tiger Trust
The Tiger Foundation: Tiger Facts − Sumatran Tiger