The Himalayas, or Himalaya, are a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the highest, Mount Everest. Over 100 peaks exceeding 7,200 m (23,600 ft) in elevation lie in the Himalayas. By contrast, the highest peak outside Asia (Aconcagua, in the Andes) is 6,961 m (22,838 ft) tall.
The Himalayas abut or cross five countries: Bhutan, India, Nepal, China, and Pakistan. The sovereignty of the range in the Kashmir region is disputed among India, Pakistan, and China. The Himalayan range is bordered on the northwest by the Karakoram and Hindu Kush ranges, on the north by the Tibetan Plateau, and on the south by the Indo-Gangetic Plain. Some of the world's major rivers, the Indus, the Ganges, and the Tsangpo–Brahmaputra, rise in the vicinity of the Himalayas, and their combined drainage basin is home to some 600 million people; 53 million people live in the Himalayas. The Himalayas have profoundly shaped the cultures of South Asia and Tibet. Many Himalayan peaks are sacred in Hinduism and Buddhism; the summits of several—Kangchenjunga (from the Indian side), Gangkhar Puensum, Machapuchare, Nanda Devi and Kailas in the Tibetan Transhimalaya—are off-limits to climbers.
Lifted by the subduction of the Indian tectonic plate under the Eurasian Plate, the Himalayan mountain range runs west-northwest to east-southeast in an arc 2,400 km (1,500 mi) long. Its western anchor, Nanga Parbat, lies just south of the northernmost bend of the Indus river. Its eastern anchor, Namcha Barwa, lies immediately west of the great bend of the Yarlung Tsangpo River. The range varies in width from 350 km (220 mi) in the west to 150 km (93 mi) in the east.
The flora and fauna of the Himalayas vary with climate, rainfall, altitude, and soils. The climate ranges from tropical at the base of the mountains to permanent ice and snow at the highest elevations. The amount of yearly rainfall increases from west to east along the southern front of the range. This diversity of altitude, rainfall, and soil conditions combined with the very high snow line supports a variety of distinct plant and animal communities. The extremes of high altitude (low atmospheric pressure) combined with extreme cold favor extremophile organisms.
At high altitudes, the elusive and previously endangered snow leopard is the main predator. Its prey includes members of the goat family grazing on the alpine pastures and living on the rocky terrain, notably the endemic bharal or Himalayan blue sheep. The Himalayan musk deer is also found at high altitudes. Hunted for its musk, it is now rare and endangered. Other endemic or near-endemic herbivores include the Himalayan tahr, the takin, the Himalayan serow, and the Himalayan goral. The critically endangered Himalayan subspecies of the brown bear is found sporadically across the range as is the Asian black bear. In the mountainous mixed deciduous and conifer forests of the eastern Himalayas, Red panda feed in the dense understories of bamboo. Lower down the forests of the foothills are inhabited by several different primates, including the endangered Gee's golden langur and the Kashmir gray langur, with highly restricted ranges in the east and west of the Himalayas respectively.
The unique floral and faunal wealth of the Himalayas is undergoing structural and compositional changes due to climate change. Hydrangea hirta is an example of floral species that can be found in this area. The increase in temperature is shifting various species to higher elevations. The oak forest is being invaded by pine forests in the Garhwal Himalayan region. There are reports of early flowering and fruiting in some tree species, especially rhododendron, apple and box myrtle. The highest known tree species in the Himalayas is Juniperus tibetica located at 4,900 m (16,080 ft) in Southeastern Tibet.