White rhinoceros Ceratotherium simum

The white rhinoceros is the largest of the five living rhino species and, after the elephants, one of the heaviest land animals on Earth. A big bull can top 2.3 tonnes, and exceptional individuals have been estimated at well over three. Despite the name, it is not white at all. Its skin is a slate grey much like that of the black rhino, and after a wallow it takes on whatever colour the local mud happens to be.

The easiest way to recognise one is to look at its mouth. The upper lip is broad, flat and square, perfectly built for cropping short grass, which is why the species is also called the square-lipped rhinoceros. It carries its long, heavy head low to the ground almost all the time, grazing in a slow sweep like a living lawnmower.

The white rhino's story is both a conservation triumph and a warning. The southern subspecies fell to perhaps a few dozen animals at the end of the nineteenth century, then recovered to tens of thousands thanks to protected areas and a pioneering relocation programme. The northern subspecies went the other way: poaching wiped it out in the wild, and only two females survive today, both in human care. This article covers the species' classification, evolution, anatomy, social life, breeding, and the long fight over its horn.

The scientific name is Ceratotherium simum. The genus name joins the Greek words for horn (keras) and beast (therion), while simum comes from a Greek word meaning snub-nosed. The species belongs to the family Rhinocerotidae, and its closest living relative is the other African rhino, the black rhinoceros (Diceros bicornis).

Nobody is entirely sure where the name came from. The most popular story says that Dutch-speaking settlers in southern Africa described the animal's mouth with a word meaning wide, and English speakers misheard it as white. It is a charming explanation, but some linguists point out that there is little written evidence for it. Other suggestions are that early specimens were coated in pale mud, or simply looked a little lighter than black rhinos.

Either way, white and black are labels of convenience rather than accurate colour descriptions. Many authors think the black rhino was named later, simply to contrast it with the white.

Two subspecies are traditionally recognised.

Genetic studies suggest the two populations have been separated for a very long time, possibly hundreds of thousands of years or more, and some researchers argue the northern form deserves full species status as Ceratotherium cottoni. Most references still treat it as a subspecies. Northern animals were described as slightly smaller and longer-legged, with a less drooping head carriage.

Rhinos arose within the odd-toed ungulates, the same order as horses and tapirs, roughly fifty million years ago. Their family tree was once far bushier than it is now, with hornless forms, hippo-like semi-aquatic species and lightly built runners. Paraceratherium, often billed as the largest land mammal that ever lived, belonged to a related lineage rather than to the true rhino family.

The two African rhinos split from a common ancestor several million years ago; published estimates commonly fall somewhere between about four and seven million years. The likely driver was diet. As Africa dried out and grasslands spread, the white rhino's line specialised in grazing while the black rhino's line stayed with browsing leaves and twigs. The white rhino's long skull, wide lips and high-crowned grinding teeth are all signatures of that grassland lifestyle.

Fossils assigned to Ceratotherium appear in Africa from around the Pliocene, and forms very close to the modern animal are known from East African deposits. The woolly rhinoceros of the Ice Age, by contrast, was not an African rhino at all; its closest living relative is the Sumatran rhinoceros.

White rhinos favour short-grass plains and open savanna dotted with trees, ideally on flat or gently rolling ground with water and shade close by. They drink regularly and love to wallow, so they rarely stray far from a water source for long.

Today the great majority of southern white rhinos live in South Africa, with smaller populations in Namibia, Kenya, Zimbabwe, Botswana, Eswatini and elsewhere. Many of these herds were reintroduced into former range, and some were moved into countries such as Kenya where the southern form never naturally occurred. A notable feature of the South African population is that a large share now lives on private ranches and reserves rather than in state parks.

The northern white rhino once roamed grasslands west of the Nile, across what is now north-western Uganda, South Sudan, the Central African Republic, north-eastern DR Congo and southern Chad. Civil wars and poaching in the late twentieth century crushed those populations. The last wild group, in DR Congo's Garamba National Park, has not been confirmed since the mid-2000s.

The white rhino is a barrel-shaped animal on short, pillar-like legs, with a very long head and a prominent muscular hump on the back of the neck. That hump anchors the neck ligaments and muscles needed to carry the heavy skull all day.

Each foot has three toes ending in broad hooves, set around a thick elastic pad that spreads the animal's enormous weight.

Two horns sit in line on the snout, a long front horn and a shorter, blunter rear one. The longest front horns on record have reportedly exceeded 150 cm.

Rhino horn is nothing like the horn of a cow or antelope. There is no bony core. Instead it is a dense mass of keratin fibres, the same protein found in human fingernails and hair, with calcium and melanin deposits in the centre that harden it. If a horn breaks or is cut off above the base, it keeps growing back at a few centimetres a year.

That simple chemistry matters. For centuries people believed rhino horn could cure fevers and other ailments, but there is no scientific evidence that chewing on compacted keratin does anything that biting your nails would not.

The eyes are small and set on the sides of the head, and the white rhino's eyesight is poor; it may struggle to pick out a motionless person at a modest distance. Hearing and smell more than compensate. The tubular ears swivel independently to track sounds from different directions, and the large nasal passages give it a keen sense of smell for reading the presence and condition of other rhinos.

The skin is thick, reaching a few centimetres in places, yet surprisingly sensitive. Hair is limited to the ear fringes and tail tip. Regular mud baths protect against sunburn and biting insects, acting as sunscreen and repellent in one.

Colour is useless for telling the two African rhinos apart, so look for these clues instead.

The white rhino is the most sociable of all rhinos. While other species are largely solitary, white rhino females and youngsters usually move in small groups, sometimes of ten or more, known in English as a crash.

Daily rhythm follows the temperature. They graze in the cool of morning, evening and night, and spend the hot middle of the day resting in shade or soaking in a wallow. Roughly half of each day goes to feeding, much of the rest to resting and sleeping, either standing up or lying down.

Dominant adult bulls hold territories, typically reported at somewhere between one and ten square kilometres depending on food and water. A territorial bull marks its patch with dung middens along regular routes, scattering the dung with his hind feet to spread his scent, and he sprays urine backwards in short bursts.

Younger or older bulls without territories may be tolerated inside a dominant male's area, as long as they behave submissively and do not try to mate. When neighbouring territory holders meet at a boundary they engage in ritual stand-offs: horn-to-horn staring, ground scraping and dung kicking. Most encounters end there, but some escalate into fights that can cause serious injury.

For all their bulk, white rhinos can sprint at over 40 km/h for short distances. Most of the time they amble slowly while grazing, but when startled the whole group may wheel and gallop off with tails curled up. They shift around their home ranges with the seasons in search of water and grass, but they do not make long-distance migrations.

White rhinos are true ecosystem engineers. By mowing tall grass down they create and maintain short-grass grazing lawns that impala, wildebeest and zebra also favour. Short-grass patches burn less readily, and research suggests that where white rhinos are abundant, the pattern of savanna fires changes. Their huge output of dung feeds dung beetles and other insects and recycles nutrients back into the soil.

The white rhino is a pure herbivore and a specialist grazer, with a particular taste for short grasses. It has no incisors or canines; the broad lips do the cropping, gathering grass in wide mouthfuls, and the massive high-crowned molars at the back grind it down.

Daily intake varies with body size and season, but adults eat tens of kilograms of grass a day. Because grass is poor in nutrients, the rhino processes large volumes through its gut. Like horses, it is a hindgut fermenter: microbes in the large intestine and caecum break down the fibre, rather than in a multi-chambered stomach as in cattle. It does not chew the cud. The trade-off is lower efficiency per mouthful, but a much faster throughput.

In the dry season, when quality drops, white rhinos broaden their menu to coarser and taller grasses and the greener growth near water. They usually drink once or twice a day, though they have been observed going two to four days without water in very dry conditions.

White rhinos can breed at any time of year, although births tend to cluster around the rainy season when grazing is best. When a female comes into oestrus, the territorial bull shadows her for days, keeping rivals away. Mating itself is a lengthy affair.

Gestation lasts about sixteen months, one of the longest among land mammals. A single calf is born, weighing around 40 to 65 kg. It stands and walks within hours and is soon moving with the group. Unusually, white rhino calves walk in front of their mothers, who steer and guard them from behind.

Females usually calve every two to three years. That slow pace means every adult lost to poaching takes many years to replace.

White rhinos communicate in more ways than you might expect. Scent is the big one. Dung middens work like a shared notice board; studies suggest that a sniff can tell a rhino who has passed by, their sex and age, and whether a female is coming into season.

They are vocal too. Mothers and calves keep in touch with thin, high-pitched squeaks, threatened animals snort and growl, and courting bulls make a distinctive panting call. Research has also detected low-frequency sounds that may carry information beyond the range of human hearing.

Body language fills in the rest. Ears pricked and head raised signal alertness, while a curled tail means excitement or alarm. Groups under threat have been seen standing rump to rump, facing outwards, with calves in the middle.

They also have good route memory. Rhinos use the same paths between water holes, wallows and middens year after year, wearing deep, well-defined trails into the landscape.

Almost nothing in the wild can take down a healthy adult white rhino; even lion prides usually leave grown rhinos alone. Calves are another matter. Lions and spotted hyenas will target them, especially if they become separated from their mothers or are weak. A mother defends her calf by charging horn-first.

Oxpeckers are frequent passengers. These birds eat ticks and other parasites and give noisy alarm calls when danger approaches; one study found that rhinos carrying oxpeckers detected approaching people sooner. The relationship is not purely friendly, though, because oxpeckers also pick at wounds to feed on blood.

In reality, the white rhino's greatest enemy has always been people. Nearly every crisis in its history traces back to hunting, poaching or habitat loss. Severe drought is the other major natural threat, since failing grass causes rapid weight loss and heavy mortality among calves and older animals.

The white rhino's history is inseparable from the history of hunting. As European settlers and hunters spread across southern Africa in the nineteenth century, this large, placid, group-living animal proved an easy target. Shooting for meat, hides and sport drove numbers down so fast that by the end of the century only a small remnant survived in what is now KwaZulu-Natal in South Africa.

Protecting that remnant, by banning hunting and setting aside reserves, was the turning point. In the mid-twentieth century a large translocation programme began moving surplus animals to other reserves and countries, and the techniques for safely sedating and transporting big mammals advanced enormously along the way.

Having been brought back from the brink, the white rhino faced a new disaster from the late 2000s. Demand for horn in parts of Asia, as a supposed medicine and as a status symbol, fuelled a surge in organised poaching. In several years South Africa alone lost more than a thousand rhinos to poachers, who used helicopters, night-vision gear and even veterinary drugs.

Reserves fought back with armed ranger units, tracking dogs, drones and camera networks, and some began dehorning sedated rhinos so they would be worthless to poachers. Because horns regrow, dehorning has to be repeated, and researchers are still studying how it affects rhino social behaviour.

In Korea, as across East Asia, rhino horn was long known as a precious ingredient in traditional medicine, valued for supposedly lowering fever and neutralising toxins. Korea joined CITES in 1993, bringing it into the international ban on commercial horn trade, and traditional remedies that once contained horn moved to substitute ingredients.

Today white rhinos are listed in Korean law as internationally endangered species, so they cannot be imported, exported or traded without a permit. White rhinos have also been kept in Korean zoos for decades, so for many Koreans the first rhino they ever saw was a white one.

On the IUCN Red List the white rhino as a whole is classed as Near Threatened. The two subspecies could hardly be more different: the southern white rhino sits at Near Threatened, while the northern white rhino is listed as Critically Endangered and is functionally extinct.

Southern white numbers peaked at around twenty thousand in about 2012, then fell under heavy poaching to an estimated sixteen thousand or so by 2021. Some later reports point to a modest recovery, though figures vary between surveys and years.

The main threats are:

• Poaching for horn and international trafficking
• Rising security costs and falling tourism income for reserves
• Drought and climate change degrading grasslands
• Small, isolated populations losing genetic diversity

The species is on CITES Appendix I, banning commercial trade, except that the southern white rhino populations of South Africa and Eswatini are on Appendix II for trade in live animals and hunting trophies only.

The last northern white bull died in 2018. The two surviving females are mother and daughter, and both are understood to be unable to carry a pregnancy naturally.

Scientists are therefore pinning their hopes on assisted reproduction. Eggs collected from the females are fertilised in the lab with sperm stored from males that have since died, and the resulting embryos are frozen. The next step is to implant them into southern white surrogate mothers. In 2024 researchers announced the world's first rhino pregnancy achieved by transferring a lab-created embryo, using southern white material, showing that the method can work.

Longer term, teams are trying to turn preserved skin cells into stem cells and then into eggs and sperm, which could widen the gene pool. Even if it all succeeds, genetic diversity and eventual return to the wild remain huge challenges, but the project has become a global test case for pulling a species back from the edge.

Because it is relatively calm and used to living in groups, the white rhino is the rhino you are most likely to meet in a zoo. In captivity it eats grass, hay and specialised herbivore pellets and needs a mud wallow, a large paddock and a heated indoor area in colder climates, where long winters indoors can bring problems with inactivity and stress.

For years white rhinos had a reputation for breeding poorly in captivity, especially females born in zoos. Researchers proposed several causes, including plant compounds in the diet that may interfere with hormones. Changes to diet and group composition, along with assisted reproduction, have since improved results.

Zoo-keeping of large, wide-ranging animals remains debated. Critics question whether any enclosure can meet the needs of a grazer built for open plains; supporters point to the value of zoo populations as genetic insurance and for research and education. The reproductive expertise built up in zoos is now central to the attempt to save the northern white.

It should go without saying, but a white rhino can never be a pet. It is a multi-tonne wild animal under strict international trade controls that needs vast space and specialist veterinary care.

With their bulk and horns, rhinos stand for charging power, toughness and stubbornness, which is why sports teams, vehicle makers and tool brands like them as mascots. Old English slang used rhino to mean money, and thick-skinned people are those who shrug off criticism.

A famous Buddhist verse urges the seeker to wander alone like the rhinoceros horn, referring to the single-horned Indian rhino. The line has been widely borrowed in Korea and elsewhere as an image of quiet, unwavering independence.

In art history, a sixteenth-century German woodcut of a rhinoceros, drawn from descriptions rather than life, became one of the most copied animal images in Europe, though it showed an Indian rhino. Eugène Ionesco's play Rhinoceros, in which townspeople turn one by one into rhinos, is a classic satire of conformity.

Rhinos turn up in films and cartoons as burly guards and lovable lunks. Every 22 September is World Rhino Day, celebrating all five species and the people working to protect them.

• White rhino middens can grow several metres across, serving as both an information exchange for rhinos and a banquet for dung beetles.
• The white rhino is one of the Big Five, the term trophy hunters once used for the five animals hardest and most dangerous to hunt on foot: lion, leopard, elephant, rhino and Cape buffalo. Today the phrase is mostly used by safari operators.
• A group of rhinos is called a crash, which suits an animal famous for charging.
• Anti-poaching teams have experimented with implanting tracking devices in horns and with treating horns to make them less attractive to traffickers.
• The white rhino's distant kinship with horses shows in its legs: in both, the body's weight rests mainly on the central toe.
• Young calves can gain well over a kilogram a day in their first months.
• The death of the last northern white bull in 2018 made headlines around the world and became a defining image of the extinction crisis.