The mammals are the class of vertebrate animals characterized by the presence of mammary glands, the presence of hair or fur; specialized teeth; the presence of a neocortex region in the brain; and endothermic or 'warm-blooded' bodies. The brain regulates endothermic and circulatory system, including a four-chambered heart. In India there are 410 species, 186 genera, 45 families and 13 orders of which nearly 89 species are listed as threatened in the International Union for Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Animals (IUCN 2006).

The yak (Bos mutus) is a long-haired bovid found throughout the Himalaya region of southern Central Asia, the Tibetan Plateau and as far north as Mongolia and Russia. Wild yaks are among the largest bovids and are second only to the gaur in shoulder height. They are also the largest native animal in their range. Wild yaks are found primarily in northern Tibet and western Qinghai, with some populations extending into the southernmost parts of Xinjiang, and into Ladakh in India.

IUCN Status: Vulnerable (VU) Photo: Dibyendu Ash