They are nearly hairless except for stiff bristles at the tip of the tail and short fringes around the ears. Some species of rhinoceroses have one large horn curving upward from their snouts. Other kinds have two. The hard horn, made of a hair like substance, keratin, grows from the rhino's skin. If a horn is broken off, a new one will grow.
Most rhinoceroses are solitary inhabitants of open grassland, savanna, scrub forest, or marsh.
In solitary species the home territory is crisscrossed with well-worn trails and tunnels through the brush, and the borders are often marked with urine and piles of dung. The animals eat a variety of vegetation, and some have prehensile upper lips that they use to grasp and tear grass, reeds, and twigs. The animal's eyes are small and shortsighted, but their senses of smell and hearing are very keen. Most rhinoceroses prefer to avoid humans, but males, particularly during the breeding season, and females with calves may charge with little provocation. Despite their names, both of these animals are gray.