Black rhinoceros

Name and taxonomy

Carl Linnaeus named the species Rhinoceros bicornis in 1758, and the name means two-horned rhinoceros. He probably worked from the skull of an Indian rhino to which a collector had added a false second horn. Once it was clear that India had only a one-horned rhino, the name passed to the African animal. In 1911 the Cape of Good Hope was fixed as the type locality. Today it is the only living species in the genus Diceros, in the family Rhinocerotidae.

The word rhinoceros is Greek, from rhino for nose and keras for horn. The word black probably arose to contrast the animal with the white rhino, whose name may come from the Afrikaans word for wide. Authors recognise between five and eight subspecies. Three are extinct, including the western black rhino, which the IUCN declared extinct on 10 November 2011.

Evolution and relatives

Rhinos are odd-toed ungulates, so their closest living relatives are tapirs and horses. The rhino family first appears in Eocene rocks of Asia and North America, about 39 to 40 million years old. Rhinos vanished from North America about 5 million years ago. Extinct relatives include the woolly rhinoceros and Elasmotherium, which weighed about 4,500 kilograms.

The black and white rhinos are closer to each other than to the Asian species. A 2021 genetic study put their split at about 7 million years ago. The direct ancestor, Diceros praecox, lived in the Pliocene of Ethiopia, Kenya and Tanzania. The oldest definite black rhino fossil comes from Koobi Fora in Kenya, about 2.5 million years old.

Appearance

An adult measures 3 to 3.75 metres in head and body, with a tail of about 0.7 metres. It weighs 800 to 1,400 kg, and a few very large bulls have been reported at up to 2.9 tonnes. Bulls are a little larger than cows. The skin is thick and almost hairless, with a fringe of short hair on the rounded ears. It shields the animal from thorns, but ticks and mites live on it.

The front horn measures 42 to 128 centimetres, the rear horn 20 to 50. Cows tend to grow longer, thinner horns than bulls, and some animals grow a small third horn. The horns are keratin, the same material as hair and fingernails, not bone. The black rhino has a smaller head, shorter ears and a higher head carriage than the white rhino. The pointed, gripping upper lip is the surest way to tell the two apart.

Habitat and range

The species once lived across most of southern and eastern Africa, and north to Sudan, Eritrea and Lake Chad. It avoided the Congo Basin, the coastal rainforest and the Ethiopian Highlands. Rock carvings in the Eastern Desert of Egypt suggest it once lived there too.

Today it survives only in guarded reserves. Namibia, South Africa, Kenya, Zimbabwe and Tanzania hold most of the animals, with smaller groups in several other countries. Malawi, Zambia, Botswana and Rwanda have all received rhinos after losing their own. In 2017 South Africa moved 18 eastern black rhinos to Akagera National Park in Rwanda, and a calf soon made 19.

The best habitat is thick scrub and bushland with some woodland. The animal also uses riverine woodland, marsh and, least of all, open grassland. One subspecies in Namibia lives in desert and semi-desert. Most rhinos stay within 25 kilometres of water, though they can go 5 days without it in a drought.

Diet and feeding

The black rhino is a browser. It eats leaves, twigs, shoots, thorny bushes, small trees, legumes and fruit, and takes grass only when it must. It has been recorded eating up to 220 plant species, with a preference for acacias and euphorbias. An adult eats about 23.6 kilograms of plant matter a day.

The hooked lip grips a branch and strips the leaves. The horns break high branches, dig up roots and scrape bark. The cheek teeth cut with one ridge and grind with others, in a two-phase chew suited to woody food. The animal feeds in the morning and evening and rests through the heat of the day.

The rhino picks quality over quantity and chooses leafy plants in the dry season. Where elephants share the range, they eat a wider menu and push the rhino toward dwarf shrubs. Rhinos also visit salt licks for minerals. Diet leaves a chemical signature in the horn, which lets police trace a seized horn to its region.

Behaviour and social life

Adults live alone. The only lasting bond is between a cow and her calf, though young animals often tag along with older ones. Cows without calves sometimes gather, and the largest group ever seen held 13 rhinos for a short time. Home ranges run from 2.6 to 133 square kilometres, smaller where food and water are close.

The rhino is not strongly territorial, and ranges overlap. Dominant bulls do challenge each other, and a meeting of two bulls can turn violent. They charge horn first and groan loudly, and the loser usually retreats. About 50 percent of bulls and 30 percent of cows die of wounds from fighting, the highest rate known in any mammal.

A startled rhino runs off with a string of snorts and its tail curled. Once calm, it often returns to inspect the cause with short curious charges. It can reach 55 kilometres per hour, running on its toes. At midday it sleeps or wallows in mud, which cools the skin and smothers parasites. Rhinos follow elephant trails between feeding grounds and water holes.

Communication and senses

Smell is the main sense. Rhinos leave dung on shared piles near feeding spots and water, and each visitor sniffs the pile before adding to it. Dung and urine tell another rhino the age, sex and identity of the animal that left them. Bulls kick through their dung to carry the scent on their feet around the range. Cows spray urine more often when they are ready to mate.

The tube-shaped ears turn in every direction and pick up sound over long distances. Eyesight is weaker, with a useful range of about 25 to 30 metres, though studies of the retina show it is better than once thought. Calls run from the pant of a mother and the squeal of her calf to a loud roar of aggression. Oxpeckers on the back may act as an early warning of danger, though some research suggests the birds also drink rhino blood.

Reproduction and life cycle

Rhinos mate in any month, but births cluster at the end of the rains in dry country. A bull follows a cow for one or two weeks, walking stiff-legged and dragging his horn along the ground. If she is not ready she charges him. When she defecates he scatters the dung so that rival bulls cannot follow her scent. A pair stays together for 2 to 3 days and mates several times, each mating lasting 20 to 40 minutes or longer.

Gestation lasts about 15 months. The single calf weighs about 35 to 50 kilograms and can follow its mother after three days. For the first week the mother hides it, and after that the two find each other by pant and squeal. The calf walks behind its mother, unlike a white rhino calf, which walks in front.

The calf browses at one month and drinks water at 4 to 5 months, but nurses for about 18 months. It stays with its mother for 2 to 4 years, until the next calf arrives. Cows first breed at 5 to 7 years and bulls at 7 to 8. A cow calves every 2 to 2.5 years in good conditions. Wild rhinos live 30 to 35 years, and a female named Fausta reached 57.

Predators and threats

An adult black rhino has no natural predators. Lions and spotted hyenas take calves, and a lion will sometimes attack an adult. A crocodile has killed an adult in rare cases. A cow defends her calf by charging, and calves probably die less often than fighting adults.

People are the real danger. Poachers kill rhinos for the horn, which sells in China and Vietnam for about 60,000 dollars a pound, about three times the price of gold. South Africa lost 1,215 rhinos to poachers in 2014, and 394 in 2020. War in Chad, Cameroon, Rwanda, Mozambique and Somalia wiped out whole populations after the 1960s. Habitat loss and competition with elephants add pressure, and captive rhinos suffer from iron overload and disease.

Population and conservation

Around 1900 several hundred thousand black rhinos probably lived in Africa, more than any other rhino. About 70,000 remained in the late 1960s and only 10,000 to 15,000 by 1981. The count fell below 2,500 in the early 1990s. It climbed back to 4,240 by 2008 and 5,500 by 2009. Save the Rhino now gives about 6,788 animals, and the IUCN counts 3,142 mature individuals.

The species as a whole is Critically Endangered, though the south-western subspecies is only Near Threatened. International trade in horn has been banned under CITES Appendix I since 1977. Reserves keep armed guards, and many move rhinos into fenced sanctuaries. Managers also saw the horn off under sedation. Research published in 2025 measured a 75 to 78 percent drop in poaching on dehorned reserves.

Namibia sold a permit to shoot one old bull for 350,000 dollars in 2014 and spent the money on anti-poaching work. The sale drew protests and death threats. In 2022 South Africa issued 10 hunting permits, saying the population was growing. Scientists have recovered eggs and sperm from dead rhinos to make embryos.

Relationship with humans

Chinese records of rhino hunting go back to 1200 BC, when horn became wine cups and hide became armour and crowns. In Yemen the horn was carved into handles for the jambiya dagger, and demand exploded in the 1970s. Traditional Chinese medicine prescribed horn for fever and convulsions, never as an aphrodisiac. China dropped horn from its pharmacopoeia in 1993, but buyers still use it for headaches, fever and cancer. No medical study supports any of these uses.

The rhino also brings tourists and money to the parks that guard it. It can be dangerous. Most charges at people and vehicles end without harm, but some cause injury, death or a wrecked car. In many reserves rangers probably know each animal by sight, and monitoring teams follow them daily.

In culture and myth

Rhinos appear in some of the oldest art on Earth. Woolly rhinos are painted on the walls of Chauvet Cave in France, about 30,000 to 40,000 years old. Carvings across the Sahara show rhinos, though it is hard to tell which species. In Khmer and Thai art the fire god Agni rides a rhinoceros. Malay, Burmese and Indian legends tell of a rhino, the badak api, that stamps out forest fires.

Europe's idea of the rhino came from a print. In 1515 the Sultan of Cambay sent an Indian rhinoceros to the king of Portugal in Lisbon. Albrecht Dürer never saw it, but he cut a woodcut from a letter and sketch and gave the animal armour plates and rivets. The rhino drowned in a shipwreck on its way to the Pope, and Dürer's picture stood as the truth until the late 18th century.

A Chinese superstition held that the hollow horn gave a direct line to Heaven. In Boston in 1974 a lavender rhinoceros became a symbol of gay visibility. Today the black rhino is probably the best known face of the poaching crisis, the animal on the posters of every anti-poaching campaign.