The White rhinoceros (Ceratotherium simum), also known as the square-lipped rhinoceros, is the largest extant species of rhinoceros and the second-largest land mammal in the world. Its alternative name, "Square-lipped rhinoceros," refers to the animal's distinctive hairless, square upper lip. The term "rhino" originates from the Africaan's word "wijd," meaning "wide," describing the mammal's broad muzzle. Though not white in color but grey, its name may have derived from the Afrikaans word ‘weit’, which means ‘wide’ and refers to their broad, square-shaped mouths.
Once nearing extinction, the White rhino has been successfully conserved. Despite current protections, these animals remain threatened by poaching for their horns. In South Africa, poaching-related mortality among White rhinos has been recently recorded.
Physical Characteristics and Subspecies
The White rhinoceros weighs slightly more on average than a hippopotamus, characterized by a massive body, large head, short neck, and broad chest. Two horn-like growths are present on its snout, composed of solid keratin, unlike the horns of bovids or antlers of deer. The front horn is larger, averaging 60 cm (24 in) in length but reaching up to 150 cm (59 in), particularly in females. White rhinoceroses also exhibit a noticeable hump on the back of their necks, and each of their four stumpy feet has three toes. The body color ranges from yellowish-brown to slate grey, with sparse hair found only on the ear fringes and tail bristles.
The white rhinoceros of Africa, scientifically known as Ceratotherium simum, can be divided into two subspecies: the northern white rhinoceros (Ceratotherium simum cottoni) and the southern white rhinoceros (Ceratotherium simum simum). Northern white rhinos live further north-currently residing in Kenya thanks to assisted colonization, though their historic range spanned from Chad and Sudan to the Democratic Republic of the Congo-while southern white rhinos occupy southern Africa.
Habitat and Distribution
Nearly the entire population of White rhinos (98.8%) is concentrated within South Africa, Namibia, Zimbabwe, and Kenya. These animals favor grasslands and open savanna woodlands, preferring flatland terrains dominated by bushes. They require constant access to grass and water sources for drinking and wallowing.
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Historically, the northern white rhinoceroses (Ceratotherium simum cottoni) were native to northwestern Uganda, southern Chad, southwestern Sudan, the eastern part of the Central African Republic, and northeastern Democratic Republic of the Congo. Southern white rhinoceroses (Ceratotherium simum simum) were native to all of southern Africa. Presently, northern white rhinoceroses only inhabit the Democratic Republic of the Congo.
Social Behavior and Territoriality
White rhinos are among the most sociable rhinoceros species, forming groups of up to 14 individuals. These groups occupy territories of at least 75-8 sq. km, varying based on habitat type and resource availability. Dominant males lead solitary lives, fiercely defending their territories against intruding males, while females and juveniles roam freely. Territorial behavior includes marking through dung spreading, urine spraying, foot dragging, and plant damage with horns. White rhinos generally tolerate other species but may engage in confrontations involving horn butting and false charges.
Daily Activities and Habits
The daily routines of White rhinos include mud baths for cooling off and parasite removal. Their activity patterns vary seasonally: they are diurnal during winter and crepuscular during summer. As megaherbivores, white rhinos are considered significant ecological engineers; their grazing patterns are thought to shape grassland structure and savanna ecology. They spend approximately half of their day feeding, a third resting, and the remainder on other activities. If water is readily available, they typically drink twice a day, but in arid conditions, they demonstrate remarkable resilience, capable of surviving four or five days without water. Like all rhinoceros species, white rhinos frequently indulge in mud wallows, coating their skin to assist in thermoregulation, protect against sunburn, and deter biting insects.
Diet and Feeding Habits
The White rhino is a herbivorous (graminivorous) mammal with a grass-based diet. They are specialized grazing herbivores, primarily inhabiting grassland and savanna ecosystems. They show a preference for the shortest grass grains and are recognized as one of the largest dedicated grazers. They tend to prefer short grasses of around 7 to 10 centimeters (3 to 4 inches) tall and use their square-shaped lips to crop the grass close to the ground. The white rhino can feed on grass continuously throughout the day.
Their distinctive broad, straight, square-lipped mouth is a feeding adaptation, allowing efficient grazing and cropping of wide swaths of grass. The name white rhino is derived from the Afrikaan word "wyt" meaning wide, referring to the broad square upper-lipped mouth that distinguishes it from the black rhino. The white rhino has no front teeth (incisors); cheek teeth are high, broad, and strongly serrated.
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An adult rhino needs to eat a large amount of food to stay nourished. Because of their size and eating capacity, rhino are considered to be ‘mega herbivores’, and are also recognised as a keystone species, having a pivotal role in defining the ecosystem. Without keystone species such as the rhino, the ecosystem would be dramatically different or cease to exist altogether. Rhino are selective in their choice of food, therefore are great eco-gardeners. Grazers keep their heads down and primarily feed on grasses with a preference for shorter grasses.
Some of the species of grasses they consume are panic grass (Panicum), signal grass (Urochloa), and finger grass (Digitaria), which are commonly found in shady areas of grasslands. Their squared-shaped lips allow them to consume vast amounts of grasses, which is why they are often cited as the largest pure grazer in the world. White rhinoceroses also eat fruits, as well as the leaves, stems, seeds, nuts, and flowers of the trees.
Reproduction and Life Cycle
Little is known about the mating system of White rhinos, although they are suggested to be polygynous. During the reproductive season, females enter males' territories to mate. Dominant, solitary bulls mate with each female for 1-3 weeks, engaging in chasing, horn clashing, and vocal communication. Mating may occur at any time of year, but generally during summer and autumn. A single calf is born after 16 months of gestation, weighing approximately 50 kg. Weaning occurs within 1-2 years, and at 2-3 years old, the young rhino is driven away by its mother before she mates again.
Females (cows) typically reach sexual maturity between six and seven years of age, whereas males (bulls) mature later, usually between 10 and 12 years. Courtship among white rhinos is often a prolonged and sometimes arduous affair. A persistent bull will often stay near a cow even when she acts aggressively, emitting calls as he approaches. He may chase or block the cow's path, vocalizing with loud squeals or wails if she attempts to leave his territory. The gestation period for a white rhino is approximately 16 months, after which a single calf is born, usually weighing between 40-65 kg (88-143 lb).
Newborn calves are unsteady on their feet for the first two to three days of life. When feeling threatened, a young calf will instinctively run in front of its mother, who is fiercely protective and will vigorously defend her offspring. Weaning typically begins when the calf is around two months old, but it may continue to suckle for more than a year. The birth interval for white rhinos generally ranges from two to three years. Before giving birth to a new calf, a mother will usually chase off her current, older calf.
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White rhinoceroses give birth to one offspring at a time, which weighs, on average, 48.5 kilograms at birth, and doubles its size by 6 months. Females reach sexual maturity at the age of 3 to 5 years, whereas males reach sexual maturity at the age of 5 to 7 years. Female white rhinoceroses can reproduce from age 5 up to the age of 46 years. The breeding interval in white rhinoceroses is long, 2.5 to 3 years. This long breeding interval is tied to a long gestational period of 530 to 550 days.
Calves usually start weaning at one year, and leave their mothers once they reach 2 to 2.5 years of age. White rhinoceros calves start suckling mother’s milk only hours after birth, and they usually suckle for 2 to 3 minutes at a time. Mothers are the sole caregivers of the young and males have no parental investment on calves beyond the mating process. White rhinoceroses start grazing at 2 months, but they are dependent on their mothers for nutrition until 6 months after birth. Beyond age 6 months, mother still nurse the child and protect them from predators and external threats, such as wildfire. Furthermore, calves usually move in front of their mother in the early stage of their life, and they respond immediately when their mothers change direction. Calves usually follow their mothers continuously for 2 months.
The average lifespan of both males and females in the wild is 46 to 50 years. The expected lifespan of white rhinoceroses in the wild is between 39 to 43 years and 27 to 30 years in captivity, on average.
Ecological Importance
White rhinoceroses are the most important herbivores across their range, grazing on vast amounts of grasses, which helps increase the biodiversity of grasses and potentially prevent wildfires. In addition, white rhinoceroses have a mutualistic relationship with several bird species, such as cattle egret (Bubulcus ibis) and Cape starling (Lamprotornis nitens), which feed on the insects and parasites present in the hide and on the back of rhinoceroses.
As they wallow in waterholes, they wash mud off their bodies, which helps distribute fertile soil in the surrounding areas. These waterholes benefit other creatures, including antelopes, who can drink from these water sources without risking getting stuck in the mud. Through their eating habits, rhinos establish and maintain short-grass ‘lawns’ which are crucial for certain plant and animal species that cannot survive in wooded or long-grass ecosystems. Every day, a white rhino consumes over 50 kilograms (110 pounds) of vegetation and deposits more than 20 kilograms (44 pounds) of dung, further enriching the soil. This dung supports its own diverse food chain, involving dung beetles, slender mongooses, and birds like crested guineafowl.
Threats to Survival and Conservation Status
These mammals currently face population decline along with other African rhinos. The primary threat is the international rhino horn trade, causing high mortality rates. The horns are used in traditional medicine in Asian markets (primarily China, Taiwan, and South Korea) and as prized material for traditional "jamiyas" in Middle Eastern markets (Yemen and Oman).
The IUCN Red List, as of 31 December 2017, estimated 18,064 White rhinos in the wild. As the end of 2023, an estimated 17,464 southern white rhinos (Ceratotherium simum simum) lived in the wild, making them by far the most abundant rhinoceros subspecies globally and outnumbering all other rhino subspecies combined. However, the northern white rhinoceros (Ceratotherium simum cottoni), is critically endangered and possibly extinct in the wild.
Organized poaching syndicates, which have historically included groups like the Janjaweed in specific regions, have been responsible for dramatically reducing rhino numbers. Historically, uncontrolled hunting during the colonial era significantly reduced white rhino populations. The demand for rhino horn is primarily fueled by its use in some traditional Asian medicines, where it is ground into powder or processed into tablets for a variety of unproven remedies for ailments ranging from fevers to cancer. Poaching levels surged dramatically in the early 21st century. This intense pressure contributes to the white…
Current Conservation Efforts
To prevent the northern white rhinoceros subspecies from going extinct, conservationists are working on techniques to create new northern white rhino embryos. One technique would include harvesting viable eggs from the remaining females and fertilizing them with sperm previously collected from male northern white rhinos.
African governments have been preserving populations of rhinoceroses in protected areas, such as Kruger National Park of South Africa, Mlilwane Game Sanctuary of Swaziland, Murchison Falls National Park of Uganda, and Meru National Park of Kenya.