Posted by Sandy Hutchens
Physical Description
Rhinoceroses (from the Greek, “nose horn”) are named for their most distinctive feature, the single or double horn on the end of the nose.
Of the five species of rhinoceros, the white (Ceratotherium simum) and black (Diceros bicornis) rhinoceroses of Africa, and the Sumatran rhinoceros (Dicerorhinus sumatrensis) have two horns in tandem, while the Indian (Rhinoceros unicornis) and Javan (Dicerorhinus sondaicus) have only one.
In the black rhino, the larger front horn measures 0.5 – 1.3 meters (16 – 52 inches) in length. Rhinos are massive animals with a large head, short neck, broad chest, thick skin and short stout legs. Each foot has three toes, which leave a cloverleaf-shaped footprint.
The black rhino is actually gray, although the color varies from yellow-brown to dark-brown depending on the color of the local soil. Adult males and females are about the same size, weighing 800 – 1,350 kilograms (1,750 – 3,000 pounds) and measuring 1.4 –1.7 meters (4.5 – 5.5 feet) at the shoulder.
The black rhino has a prehensile (adapted for seizing or grasping) upper lip that it uses for grasping branch ends, and from which it gets the name “hooked-lipped rhino.”
Rhinos have a poor sense of sight but a good sense of hearing and a keen sense of smell. The testes of the male do not descend into the scrotum as with most mammals, and females have one pair of teats between their back legs.
Calves are born weighing about 40 kilograms (88 pounds) and have a pink hue to their color that fades to gray as they age.
Natural History
There are four subspecies of black rhinoceros; the southern-central black rhino (D.b. minor), the south-western black rhino (D.b. bicornis), the east African black rhino (D.b. michaeli) and the west African black rhino (D.b. longipes).
Historically, the four subspecies inhabited different areas throughout sub-Saharan Africa, except for the tropical forest of the Congo Basin.
Today, their distribution has been radically affected by hunting and habitat loss, and now only patchily distributed animals survive within guarded game reserves and private parks.
The black rhinoceros lacks incisors and canine teeth. Instead, it uses the upper lip to grasp woody plants, along with some forbs (herbs other than grass) and fruits.
Black rhinoceroses depend on water almost daily but can go for up to five days without a visit to the watering hole. They are often found wallowing in the water holes, coating themselves in mud to help protect against biting insects.
Adult male black rhinos are usually solitary except during mating, and adult females are also found alone except for mothers with calves. Adults of both sexes, however, may join up to form pairs or larger groups for short periods of time. Adult males have vicious fights with each other for receptive females. They have the highest incidence of death from fighting of any mammal.
Female black rhinos reach sexual maturity between four and seven years of age. Males reach sexual maturity between seven and eight years of age but do not attain dominant status until closer to ten years.
A single calf is born every two to four years, although the calving interval may be as short as 22 months. Most calves are born during the dry season and are weaned at about one year of age. They are driven away by the mother between two and three years of age just prior to the birth of her next offspring.