Black Rhinoceros – Diceros bicornis

Damara, first time mother and her calf from Howletts Wild Animal Park near Canterbury in Kent. Source: Daily Mail

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Conservation

• The IUCN Red List of Threatened Species lists the Black Rhino as Critically Endangered.
• The species is listed on CITES Appendix I.
• International trade in Black Rhinos and their products is prohibited.

Fun Facts about Rhinos

• Rhinos are one of the oldest groups of animals.
• They provide important source of income from ecoturism.
• In 1961 WWF was the first organization to launch an international effort to save black rhinos from extinction.
• Their name come from two Greek words, rhino meaning nose and ceros meaning horn.
• A group of rhinos is called a crash.

Name

• Common Name: Black Rhinoceros, African Black Rhinoceros, Black Rhino.
• Scientific Name: Diceros bicornis

Distribution

• Its original distribution comprised the entire African continent south of the Sahara except for the Congo Basin. Currently the Black Rhino’s distribution is very fragmented.
• Central-West Black Rhino (Diceros bicornis longipes) – Extinct
• Southern-central Black Rhino (Diceros bicornis minor) – South Africa and to a lesser extend Zimbabwe. Small numbers remain in Tanzania.
• Southern-western Black Rhino (Diceros bicornis bicornis) – Namibia and South Africa.
• Eastern Black Rhino (Diceros bicornis michaeli) – Kenya and small numbers in Tanzania

Black Rhino distribution map. Adapted from IUCN.

Population

• The Central-West Black Rhino subspecies has been completely wiped out from earth.  The Black Rhino species as a whole has seen its population decline by approximately 97.6% since 1960.
• There were 2,410 Black Rhinos in 1995. In 2010 numbers were improving with 4,880 individuals.
• As of December 2010 the estimated population of wild black rhinos were as follows: 2,200 Southern-central Black Rhinos, 1,920 South-western Black Rhinos, and 760 Eastern Black Rhinos.
• During the second half of the 20th century hunting, large scale poaching and land clearance comprised for the almost disappearance of the species.
• About 96% of the wild Black Rhinos are in South Africa, Namibia, Zimbabwe and Kenya.

Habitat

• Most rhinos live in savannas with nutrient rich soils. However they are also found in forests, tropical and subtropical.
• They usually choose to stay within 25 km from a source of water.

Physical Features

• Black Rhinos are not actually black. Their skin color fluctuates from yellow-brown to dark brown but the majority is grey. Their coloration depends on the habitat.
• The difference between black and white rhinos is that Black Rhinos have a pointed upper lip while White Rhinos have a square upper lip.
• They have two horns which grow as much as 3 inches (8 centimeters) a year. The front one is the largest one. They use them to protect themselves and their young. Females have longer and thinner horns than males.
• Their skin is hairless except for the short hair on their ears.

Size and Height

• Males are slightly larger than females.
• They measure between 55 to 71 inches (1.4 to 1.8 meters) at shoulder height.
• Their head and body length is between 9.8 to 2.5 feet (3 to 3.75 meters).
• Black Rhinos weight between 1,764 to 3,086 lb (800 to 1,400 kg).

Behavior

• These mammals are herbivores. Black Rhinos are browsers and get their nutrition from eating trees, bushes, branches and fruits, they show a preference for acacia. They eat an average of 52 lb (23.6 kg) of food a day.
• The basic social unit is the mother and her calf. Males are solitary until is time to mate. Temporary associations are sometimes formed but they do not last long.
• Black Rhinos are diurnal, they eat during the night, dawn and dusk and during the day they rest under the shade.
• They protect their skin from the sun and against bugs by rolling in mud.
• They have a strong sense of smell.
• They mark their territory by defecating and urinating on it. They show aggression if another rhino enters its territory.
• Home range varies depending on the habitat. They fluctuate from 1.62 to  82.6 sq miles (2.6 sq km to 133 sq km). A smaller home range is the result of better habitat condition in which water and food are readily available. Under poor conditions the animals have to travel longer distances to a water source and look around for food.

Reproduction

• Black Rhinos are polygynous. They breed at any time of the year but peak season varies by location. They breed every 2 to 4 years.
• Males reach sexual maturity at around 7 to 8 years, while females between 5 to 7 years.
• Gestation lasts about 15 months.
• Calfs are weaned after 18 months but they remain dependent on their mothers for up to 4 years. They have to leave when the mother has another offspring.

Life Expectancy

• In the wild Black Rhinos live between 30 to 35 years.
• In captivity they can live over 45 years.

Predators

• Lions and spotted hyenas prey on young rhinos.
• The most dangerous predator of Black Rhinos are humans.

Threats

• Black Rhinos are primarily killed for the commercial demand of their horns used in Traditional Chinese Medicine. Horns are also used in ceremonial traditions in some Middle Eastern countries.
• Civil war in African countries has had negative effect on conservation efforts, as people faced with violence trade rhino horns for machine guns to protect themselves.
• Encroachment of rhinos’ habitat as more people move into rhino lands to convert them into agricultural land.

References and Further Research

• ITIS Report – African Black Rhino
• WWF – Black Rhino
• Scientific American – How the Western Black Rhino Went Extinc
• IUCN Red List of Threatened Species – Diceros bicornis
• University of Michigan Museum of Zoology – Diceros bicornis
• Smithsonian National Museum of Natural History
• Denver Zoo – Black Rhonoceros
• WAZA World Association of Zoos and Aquariums -Black Rhinoceros
• Cites Appendix I