The name rhinoceros comes from the Greek words for "nose-horn" (rhino-ceros). Rhinoceroses are the only mammals with horns on their noses rather than on top of their heads. The origin of the rhino family stretches back 60 million years to five million years after the reign of the dinosaurs.

Physical Characteristics of Indian Rhino :
The great Indian one-horned rhinoceroses (Rhinoceros unicornis) are the second largest of five rhino species, standing five and a half to six feet tall, weighing up to 5,000 pounds, and reaching up to 12 feet long. The female rhinos weigh less than the males. The distinctive horn present in both males and females, but not newborn young, is made of keratin — the same protein that forms fingernails and the covering of cow horns.

Habitat, Habits and Social Life :
The one-horned rhinos inhabit floodplain grasslands and adjacent forests and swamps. However, today, in their restricted range, they sometimes feed in cultivated fields and pastures. The males generally travel alone, feeding under the dense cover of tall grass or trees, and spending hours wallowing in mud, an activity that keeps biting flies at bay. Females and their young travel together, and sometimes a few rhinos will share the same feeding or wallowing areas. The male rhinos are territorial.

The one-horned rhinos are strict vegetarians, mainly eating grasses, but they also consume leaves, fruit, branches, and farm crops.

The female rhino reach breeding age at 5 years and bear their first calves between 6 and 8 years of age. Single calves are born at intervals of about three years. Males can breed at about 9 years of age but due to competition from older males, many do not mate until they are about ten years old. In zoos, one-horned rhinos have lived up to 47 years, however due to tuff conditions and struggle for survival, the longevity in the wild is shorter.

Present situation of Rhino in India :
The one-horned rhino once ranged from Pakistan across northern India to Nepal, Bhutan, and the border with Myanmar (Burma), and perhaps ranged even further, into southern China. Today, rhino is found only in pockets in the north-eastern state of Assam in India and in Nepal.

There are about 1900 one-horned rhinos in the world, and of these about 60% are in India and are endangered. The population of the one-horned rhinos has drastically declined since the early part of the 20th century due to many reasons. First of all, their river-side grasslands were replaced by farmland. Trophy hunting and a bounty placed on rhinos by tea growers (the animals chewed their crops) pushed them to the brink of extinction. However, today, the biggest problem is poaching of the animal for their horns and other parts.

In India, the habitat of the great one-horned rhinos is limited to two National Parks in the north-eastern state of Assam— the Kaziranga National Park and the Manas Tiger Reserve.