Adaptation can be defined as “structural and physiological adjustments in organisms to cope with fluctuations in its immediate environment.”
High-altitude biotic complex is unique in its hostile environment, comprising difficult terrains, low temperature and atmosphere pressure to which all wildlife has to adjust for successful survival.
Animals fight for survivals at high altitudes with bizarre and varied adaptations. Such adaptation have resulted in special features such as evolution of certain members of some animal families of Cervidae, Canidae and Felidae; and proliferation of genera adapted to mountain habitats- Capra Ovis, Capricornis and other into a number of species and sub species.
Animal living at high altitude exhibits a striking number of adaptations in terms of morphology, physiology and behavior.
Adaptations are the main modification induced both by environment and genetics evidenced by existence of animals pre-adapted to particular habitat e.g. Yak adapted not only to high altitude arctic and desert conditions and tamed as one of the highest dwelling animals of the world.
Those high altitude animals which can withstand relatively greater differences in altitude are termed as Eurybarc e.g. Yak, Ibex, Tibetan Gazelle of the Himalayas and Vicunas Illamas of Andes. Stenobarc includes that high altitude animals which have the ability to endure lesser differences in altitude e.g. rabbits, mountain goats, shop and cats. Man holds a transitional position between the two groups.
The 80 million years old Indian Himalayan composed to 8 million year old Andes of South America has enjoyed more time for genetic adaptation and evolution of its diversified spectrum of wildlife species resulting in more than 50 wool/fur bearing animals in the Himalayas composed to 5 or 6 in the Andes e.g. Illamas, Alpaca, Vicuna and famous chinchilla.
Among the herbivores of the Himalayas, the Himalayan Tahr, Morkhor and Chamois are of special interest because of their ecological versatility and tolerance. Born with the mountains and shaped by them, many Caprines seem to have retained a certain plasticity that enables them to adapt to the constant environmental changes in the rocky realm (Schaller, 1977).
Truly speaking, very few large mammals have been able to adapt themselves to high altitude environment which is particularly true of the mountain of the continents other than Asia where vast tracts are devoid of large mammalian element.