The black rhinoceros (Diceros bicornis) is the most well known of the five living rhinoceros species, with its aggressive reputation and highly publicised international conservation drive. Black rhinoceros are in fact grey in colour and are distinguished from the other African species (which is also grey) the white rhinoceros (Ceratotherium simum), by its pointed, prehensile upper lip; white rhinoceros have square lips (2). Both African rhinoceros species possess two horns, made from clumped fibres rather than bone, and the taller front horn may be 60 centimetres or longer (4).
Black rhinoceros are mainly solitary creatures, occupying overlapping home ranges (5). In this long-lived species females reach sexual maturity at around five to seven years old and give birth to a single calf every two to four years (6). Births can occur throughout the year and each calf tends to remain with its mother until the birth of her next offspring. Rhinoceros have poor eyesight but a keen sense of smell and hearing (5). They are inquisitive and often aggressive towards humans and other animals (4).
Using their prehensile lip, black rhinoceros feed on the leaves and twigs of a variety of woody plants and herbs (4). Foraging often occurs in the cool of dawn and dusk; they spend much of the rest of the day resting in the shade or wallowing in shallow water holes, coating their skin in mud to protect it from the harsh sun and to deter biting flies (2).
Once found throughout much of sub-Saharan Africa with the exception of the Congo Basin and other equatorial forest areas of West Africa (4). The recent decimation of the black rhinoceros has restricted the range to fragmented populations, predominately existing in reserves in Kenya, Tanzania, Namibia, Zimbabwe, South Africa, Cameroon, Malawi and Swaziland (4). Four subspecies are recognised in different areas of the species range: the southwestern (Diceros bicornis bicornis), western (D. b. longipes), eastern (D. b. michaeli) and south-central black rhinoceros (D. b. minor) respectively (1).
The black rhinoceros is classified as Critically Endangered (CR) on the IUCN Red List (1) and is listed on Appendix I of CITES (3).
Subspecies: southwestern black rhinoceros (D. b. bicornis) classified as Vulnerable (VU); eastern black rhinoceros (D. b. michaeli) and south-central black rhinoceros (D. b. minor) are both classified as Critically Endangered (CR); western black rhinoceros (D. b. longipes) classified as Extinct (EX) on the IUCN Red List (1).
Black rhinoceros have been poached to the brink of extinction due to the demand for their horn, both for use in Chinese traditional medicine and for traditional dagger handles in Yemen, the demand for which exploded in the 1970s due to the increased income of oil-rich Gulf States (7). It is estimated that between 1970 and 1992, around 96 percent of the black rhinoceros population was lost (8).
The population crash in the latter half of the 20th Century saw rhinoceros numbers plummet to a low of about 2,400 individuals (4). A variety of conservation approaches have been adopted, which have resulted in the stabilisation and partial recovery of populations in a number of countries. The most successful have involved the rigorous protection of rhinoceros in fenced sanctuaries, often in partnerships between the State and private sectors, or in intensely protected unfenced zones within larger areas (4). Dehorning has also been used in some countries to reduce the incentives to poach (4). In 1997, Yemen became a signatory of the Convention on International Trade in Endangered Species (CITES), thus greatly reducing the demand for rhinoceros horn in the Middle East (7). By 2001, the continental black rhinoceros population had increased to 3,100, with populations in six of the eight range states increasing (4). Most individuals are conserved in heavily protected areas. The African Rhino Specialist Group of the World Conservation Union (IUCN) provides advice on the conservation of African rhinoceros, and has developed a detailed Action Plan, which provides extensive information and strategic direction for their conservation (4).
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