Deers come under the Order Artiodactyla which comprises alt the even-toed ungulates. They come under three families in the order: Moschidae, Cervidae and Bovids. While the first two are exclusively formed of deers, Bovids - under which the family of antelopes comes, also have other ungulates present.
Moschidae is the family which comprises of musk deer. Two species of musk deer are found in India, the Himalayan musk deer and the Black musk deer. Both these species are found in the Himalayan and adjoining areas and are classified "endangered" by the IUCN.
Cervidae is the family which comprises the deer proper. There are seven species from this family which are present in India. These include the Sambar deer, Chital or Spotted deer, Hog deer, Barking deer, Barasingha / Swamp deer, Hangul or the Kashmir stag, and the Brow - antlered deer or the Manipuri sangai. Apart from the chital which is commonly found throughput India, the other species of deer have either been classified as "vulnerable" or "endangered" by the IUCN. Sambar deer is India's largest and most common deer.
There are six species of antelopes present in India. Of these six, the Nilgai and Chousingha (Four horned antelope) are restricted to peninsular India and is believed to be the primitive stock from which wild cattle evolved. The two gazelles (lndian an Tibetan) and the Blackbuck are slender bodied, long limbed with annulated horns. The Tibetan Antelope or Chiru has a luxuriant coat that helps it to survive extreme temperatures up to -40 degrees by Centigrade.
The population of deers in the natural forests is very important as they form the prey base to the larger cats like tiger and leopard and this prey-predator relationship helps to sustain the population of both the species.