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Unique Animals
The wild yak weighs up to 1,000 kilograms. It occurs in treeless uplands,
including plains, hills, and mountains, from as low as 3,200 meters up to the
limit of vegetation at about 5,400 meters. It stays in high areas with permanent
snow during the warmer months of August and September, and spends the rest of
the year at lower elevations. The wild yak grazes on grasses, herbs and lichens.
Ordinarily it gathers in groups of 10 - 30 or more, but at times may be in large
groups of 100 - 200.
The wild yak, which was once numerous and widespread on the entire Tibetan
plateau north of the Himalayas, now is largely found in this depopulated area.
 The yak was probably domesticated in Tibet during the first
millennium B.C., and domesticated yaks now occur throughout the high plateaus
and mountains of Central Asia, in association with people. Yaks found in zoos
are also usually of the domesticated variety, which is smaller than the wild
yak.
The wild yak is supremely well adapted to the harsh highlands with its thick
coat, great lung capacity, and ability to clamber nimbly over rough terrain.
Even its blood cells are designed for high elevations - they are about half the
size of those of cattle and are at least three times more numerous, thus
increasing its blood's capacity to carry oxygen. Its thick coat and low number
of sweat glands are also efficient for conserving heat. In winter the yak can
survive temperatures as low as - 40 degrees C.
Author: Jeff
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