Biology Reference
In-Depth Information
tains (South and Southeast Asia), and musk deer (Himalayan regions)—may be the result of
another strong selection pressure. The ability to avoid detection by prowling leopards would
be a behavioral trait that natural selection would reward. So perhaps a feature that was selec-
ted for eons ago serves well today. A muntjac or saola skilled at evading detection by leo-
pards must be hard to find for predatory humans, too.
As was true in New Guinea, understanding a bit of the area's geologic history can explain
a lot about the current concentrations of rarities in Indochina. About 350 million years
ago, the Annamites arose during collisions of Earth's plates. They are truly ancient moun-
tains—much, much older, for example, than the Nepal Himalayas, at about 55 million years
old. The Himalayas emerged when what is now India broke off from the ancient supercontin-
ent known as Gondwanaland and rammed into Eurasia. Initially, the joining of the subcon-
tinent of India with Eurasia opened a vast new landmass for the invasion of novel species.
Then the uplift of the Himalayas and the Tibetan Plateau sealed off Southeast Asia from the
northern part of the continent, preventing new invasions. This event isolated the Annamite
fauna and flora.
Other mountain chains arose in the northwest of Vietnam, followed by the emergence of
highlands in the northeast. Changes in river courses and, along the coasts, the rise and fall
of sea levels successively isolated and rejoined populations of plants and animals. When sea
levels were low, connection by land bridges to the south allowed an Indonesian influence to
reach the flora and fauna of Indochina. In addition, cyclic weather patterns featuring winter
monsoons and summer rains drenched some areas and passed over others.
In sum, we can see in Indochina all the ingredients for a rarity stew. Ancient mountain
range developments and shifting patterns of water and land promoted conditions of physical
isolation conducive to speciation, as did variegated patterns of warm temperature and precip-
itation. The narrow bands of wet and dry forest resulted in a rich mosaic, offering a diverse
range of habitats where species could settle and might remain in isolation from one another.
The search for further evidence of the Javan rhino in Indochina picked up in earnest in 2003,
when an energetic Dutch biologist, Gert Polet, began supervising fieldwork in Cat Tien Na-
tional Park. His team looked for rhino spoor, any sign that this elusive creature persisted in
the former battleground. Cat Tien, about 100 kilometers south of the terminus of the Ho Chi
Minh Trail, had been an important staging area for soldiers going into the south. US and
South Vietnamese regulars came here to stop them. There is no record of any encounter with
Javan rhinos during the battles, and Polet's team found no evidence on the ground.
Polet's team's use of infrared camera traps had an important precedent in an attempt to
catch the phantom mammal on film. One of these traps, set in 1998 by WWF scientist Mike
