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 white-bellied must deer or Himalayan must deer (Moschus leucogaster) is a musk deer species occurring in the Himalayas of Nepal, Bhutan, northern India including Sikkim, and China. White-bellied must deer are very well adapted for high altitudes. The male must deer secrets a waxy substance called must from a gland in the abdomen. The deer use this to mark territories and attract females. The must is also used in the manufacture of perfumes and medicines. During the day, white-bellied must deer hide in dense cover. At night, they emerge to feed in more open habitats.

IUCN Status: Endangered (EN) Photo: Puran Singh