The hide is generally gray brown, becomes pinkish in the skin folds, and is covered with rivetlike knobs. Males show enormous development of the neck folds. The greater Indian rhinoceros originally occurred mainly in alluvial plain grasslands, where the grass grew up to 8 meters tall. It also was found in adjacent swamps and forests. Its range now has been so restricted by human activity that it often must use cultivated areas, pastures, and modified woodlands.
Activity takes place mostly at night, in the early morning, and in the late afternoon.
The middle of the day commonly is spent resting in the shade or in mud wallows. The diet consists mainly of grass and also includes fruit, leaves, branches of trees and shrubs, and cultivated crops. When feeding on tall grasses, R. unicornis curls its prehensile upper lip around the grass stems, bends the stems over, and bites off and chews the tops, drawing the tips into the mouth from the side. Drinking takes place on a daily basis, and mineral licks are visited regularly. Apart from cow-calf pairs, groups are rare.