White Rhinoceros

About the white rhinoceros

The white rhinoceros, also known as the white rhino or square-lipped rhinoceros, is the largest living species of rhinoceros and the most social of the five rhino species. Judged by mean body mass, only the three living elephant species outweigh it, and even though individual white rhinos and hippopotamuses can overlap in mass, the white rhino weighs more on average. Its bulk shows in a large, barrel-shaped body and an immense head connected to the shoulders by a short, powerful neck.

Bulls typically measure 3.7 to 4 m (12.1–13.1 ft) in head-and-body length and stand 170 to 186 cm (5.58–6.10 ft) at the shoulder, while cows measure 3.35 to 3.65 m (11.0–12.0 ft) long and 160 to 177 cm (5.25–5.81 ft) at the shoulder; the tail adds roughly 70 cm (28 in) to total length. Bulls average 2,000 to 2,300 kg (4,410–5,070 lb), and cows average about 1,600 to 1,700 kg (3,530–3,750 lb). Individuals up to 3,600 kg (7,940 lb) are considered reliably recorded, though claims of animals as heavy as 4,500 kg (9,920 lb) remain unverified. Its two horn-like structures — not true horns, but solid masses of compacted keratin, the same protein in human hair and fingernails — sit one behind the other on the snout. The front horn is usually the larger of the two, averaging 60 cm (24 in), though in some individuals, particularly cows, it can reach 166 cm (65 in); a single horn can weigh around 4.0 kg (8.8 lb). A muscular hump behind the neck helps support the head during long bouts of grazing, and the thick, grey, armor-like skin often takes on the color of the local soil from mud wallowing. Its most distinctive feeding adaptation is a broad, straight, square-lipped mouth built for grazing efficiently across wide swaths of grass, and it relies more on smell and hearing than on its relatively poor eyesight; its nostrils are the widest of any land animal and its olfactory passages are larger than its brain.

The species includes two subspecies with sharply different fates. The southern white rhinoceros numbered an estimated 17,464 individuals in the wild as of the end of 2023, with South Africa the stronghold at 12,968 animals in 2021 and smaller populations in Namibia, Botswana, Zimbabwe, Uganda, Eswatini, Mozambique, and reintroduced ranges in Kenya and Zambia. The northern white rhinoceros is critically endangered, and effectively extinct in the wild: its last known male, Sudan, died in March 2018, leaving only two females, Najin and Fatu, both at Ol Pejeta Conservancy in Kenya.

Behavior and diet

White rhinos are specialized grazers of grassland and savanna, favoring the shortest grass and ranking among the largest dedicated grazers on Earth. A typical day is roughly half spent feeding, a third resting, and the remainder on other activity. They drink twice a day when water is plentiful but can go four or five days without it in arid conditions. Like other rhinos, they wallow frequently in mud, which helps regulate body temperature, guards against sunburn, and deters biting insects. As megaherbivores, white rhinos are considered ecological engineers whose grazing shapes grassland structure and savanna ecology, playing a role similar to that of African elephants; losing large herbivores like these can trigger cascading effects on other species.

Communication runs through a range of vocalizations — a panting contact call, grunts and snorts during courtship, distress squeals, and deep bellows or growls when threatened — and these calls differ between the northern and southern subspecies and even between individuals. Despite their size, white rhinos can run up to 64 km/h (40 mph) in short bursts and sustain around 30–31 mph (48–50 km/h) for a good stretch, with solid stamina to back it up.

Socially, white rhinos form groups called "crashes," typically up to 14 animals, mostly cows and calves; sub-adult bulls sometimes group together or with an adult cow, but most adult bulls live solitary lives. Dominant bulls are territorial, maintaining 20 to 30 dung piles, or middens, to mark their ground, along with horn-rubbing, ground-scuffing, and urine spraying — patrols and marking can happen up to ten times an hour within a bull's territory. Subordinate bulls don't establish or mark territories of their own, and the most intense fights between bulls erupt over mating access to receptive cows. Cows' territories overlap extensively and are not similarly defended.

Range and habitat

The southern white rhinoceros is found primarily in South Africa, with smaller reintroduced populations in Namibia, Botswana, Zimbabwe, Uganda, and Eswatini, a small surviving population in Mozambique, and introduced populations in Kenya and Zambia outside the subspecies' historical range. The northern white rhinoceros was formerly found across several countries in East and Central Africa south of the Sahara as a grazer of grasslands and savanna woodland, but is now reduced to two captive females at Ol Pejeta Conservancy in Kenya.

Both subspecies depend on open grassland and savanna habitat suited to grazing on short grasses.

Conservation status

The white rhinoceros is listed as Near Threatened on the IUCN Red List, in a 2020 assessment, a status driven primarily by poaching for its horn and by habitat loss. The two subspecies tell very different stories. The southern white rhinoceros remains the most abundant rhino subspecies in the world, outnumbering all other rhino subspecies combined at an estimated 17,464 individuals as of the end of 2023. The northern white rhinoceros, by contrast, is critically endangered and possibly extinct in the wild: after its last fertile males died in 2014 and its last male, Sudan, was euthanized in 2018 due to age-related health problems, only two females remain, both under close management at Ol Pejeta Conservancy. Conservationists hold out hope for assisted reproduction using stored semen from Sudan and other deceased males, though the quality of aged semen and the complexity of the procedures involved present significant obstacles.