Sumatran
tiger (Panthera tigris sumatrae) is a subspecies of tiger found on the
Indonesian island of Sumatra. Recent genetic testing has revealed the
presence of unique genetic markers, which isolate Sumatran tigers from
all mainland subspecies. About 400-500 wild Sumatran tigers were
believed to exist in 1998, but their numbers have continued to decline.
According to the RSPB in March 2008 there were approximately 300
Sumatran Tigers remaining in the wild.
The
origin of fauna in Indonesia is heavily affected by geographical and
geological events on the Asian continental landmass and the Australasian
continental landmass (now Australia). The present New Guinea island was
connected with the present Australia continent, forming a
supercontinent called the southern supercontinent Gondwana. This
supercontinent began to break up 140 million years ago, and the New
Guinea region (previously known as Sahul) moved towards the equator. As a
result, animals from New Guinea traveled to the Australian continent
and vice versa, creating many different species living in different
ecosystems. This activities continued to occur until the two regions
separated completely.
The
influence of the Asian continental landmass, on the other hand, was the
result of the reformation of the Laurasia supercontinent, which existed
after the breakup of Rodinia around 1 billion years ago. Around 200
million years ago, the Laurasia supercontinent split completely, forming
Laurentia (now America) and Eurasia continents. The mainland of the
Eurasia continent, including China, was not separated completely from
the Indonesian archipelago. As a result, animals from the Eurasia
mainland could travel to the archipelago, and, under a different
ecosystems, new forms of species were formed.
In
the nineteenth century, Alfred Russel Wallace proposed the idea of the
Wallace Line, a notional line dividing the Indonesian archipelago into
two regions, the Asian zoogeographical region (Sundaland) and the
Australasian zoogeographical region (Wallacea). The line runs through
the Malay Archipelago, between Borneo and Sulawesi (Celebes); and
between Bali and Lombok. Although the distance from Bali to Lombok is
relatively short, only about 35 kilometres, the fauna distribution is
still affected by the line. For example, a group of birds would refuse
to cross even the smallest stretches of open water. A second line, lying
east, known as the Webber Line, has also been proposed to separate
between "transition species" and species of Australian origin.
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