Physical Characteristics
The Rhinoceros is a large, primitive-looking mammal that in fact dates from the Miocene era millions of years ago. The Rhino is an endangered species because it is hinted for its horn which is thought to have some medicinal value. In recent decades rhinos have been relentlessly hunted to the point of near extinction. Since 1970 the world rhino population has declined by 90 percent, with five species remaining in the world today, all of which are endangered.
The white or square-lipped rhino is one of two rhino species in Africa. It in turn occurs as two subspecies, the southern and the northern. The southern dwindled almost to extinction in the early 20th century, but was protected on farms and reserves, enabling it to increase enough to be reintroduced. The northern white rhino has recovered in Democratic Republic of Congo from about 15 in 1984 to about 30 in the late 1990s. This population, however, has recently been severely threatened by political conflict and instability.
The white rhino's name derives from the Dutch word "weit," meaning wide, a reference to its wide, square muzzle adapted for grazing. The white rhino, which is actually gray in color and has a pronounced hump on the neck and a long face.
The black, or hooked-lipped, rhino, along with all other rhino species, is an odd-toed ungulate - three toes on each foot. It has a thick, hairless, gray hide. Both the black and white rhino have two horns, the longer of which sits at the front of the nose.

Habitation
Black rhinos have various habitats, but are mainly found in areas with dense, woody vegetation. White rhinos live in savannas with water holes, mud wallows and shade trees.

Behavior and Habits
Rhinos live in home ranges that sometimes overlap with each other with feeding grounds, water holes and wallows shared. The black rhino is usually solitary. The white rhino tends to be much more gregarious. Rhinos are also rather ill-tempered and have become more so in areas where they have been constantly disturbed. While their eyesight is poor, which is probably why they will sometimes charge without apparent reason, their sense of smell and hearing are very good. They have an extended "vocabulary" of growls, grunts, squeaks, snorts and bellows. When attacking, the rhino lowers its head, snorts, breaks into a gallop reaching speeds of 30 miles an hour, and gores or strikes powerful blows with its horns. Still, for all its bulk, the rhino is very agile and can quickly turn in a small space. The rhino has a symbiotic relationship with ox-peckers, also called tick birds. The birds eats off ticks on the rhino body and noisily warns it of any danger. Although the birds also eat blood from sores on the rhino's skin and thus obstruct healing, they are still tolerated.
The closest rhino relationship is between a female and her calf, lasting from 2 to 4 years. As the older calves mature, they leave their mothers and may join other females and their young, where they are tolerated for some time before living completely on their own.

Diet
The black rhino is a herbivore and a browser, with a triangular-shaped upper lip ending in a mobile grasping point. It eats a large variety of vegetation, including leaves, buds and shoots of plants, bushes and trees. The white rhino, on the other hand, is a grazer feeding on grass.

Predators and Threats
Man is the cause of the demise of the rhino. In the wild, the adult black or white rhino has no true natural predators and, despite its size and antagonistic reputation, it is extremely easy for man to kill. A creature of habitat that lives in a well-defined home range, it usually goes to water holes daily, where it is easily ambushed. The dramatic decline in rhino numbers is unfortunate in an era of increasing conservation and wildlife awareness, but efforts are underway to save the rhino from extinction.

Thought You should Know

• The black rhino declined drastically in the 1970s and 1980s due to poaching. To prevent extinction, many rhinos were trans located to fenced sanctuaries in the early 1990s. This effort appears to be succeeding, as 1994 was the first time in 20 years that rhino numbers did not decline.

• The rhino is prized for its horn. Not a true horn, it is made of thickly matted hair that grows from the skull without skeletal support. The major demand for horn is in Asia, where it is used in traditional medicine and ornamental carvings.