|The white rhino, or square-lipped rhinoceros, is the second largest land mammal on the planet. Distinguished from the black rhino by its wide, flat lip, the white rhino is perfectly built for grazing upon grasses and leaves while holding its face parallel to the earth.|
The white rhino may be distinguished externally from the sympatric black rhino (Diceros bicornis) by a larger size, presence of a nuchal hump that is more obvious when the head is held up, a long head, square lip, enlarged horn-bases, and a straight back with marked presacral.
The white rhino’s head is normally held low and the lips are flat, squared, and broad, suitable for grazing. The lower lip bears a hardened pad.
White rhinos have two horns of unequal size. The horns are composed of keratin, like true horn, though they lack a bony core and are unattached to the skull, resting on nasal- and frontal-bone pedicels, continually growing. The recorded length of longer horns is 1,660 millimeters in length. The shorter horns can grow up to 550 millimeters in length. Female white rhinoceroses have longer and thinner horns than males.
The average length of the white rhino’s head and body, not including the tail, is 3.35 to 3.77 meters. The average length of the tail ranges from 0.57 to 0.77 meters. In addition, white rhinoceros average shoulder height is 1.71 to 2.85 meters, whereas the average girth is between 2.01 and 2.20 meters.
Females are also slightly smaller than males. White rhinoceroses are one of the largest terrestrial mammals and weigh approximately 1,000 to 3,600 kilograms as adults. The average length of their head and body, not including tail, is 3.35 to 3.77 meters. The average length of tail of white rhinoceroses ranges from 0.57 to 0.77 meters. In addition, white rhinoceros average shoulder height is 1.71 to 2.85 meters, whereas their average girth is between 2.01 and 2.20 meters.
White rhinoceroses actually have pale gray to dark brown skin which is dense, tough, and has plate-like folds. The epidermis of white rhinos is 1 millimeter thick and their dermis is 18 millimeter thick, on average. The skin is generally hairless except for ear fringes and stiff bristles terminating the long, thin tail.
The lifespan of white rhinos differs between captivity and in the wild. The average lifespan of both males and females in the wild is 39 to 50 years. The recorded longest lifespan of northern white rhinoceroses in captivity is 30 years and 3 months. Similarly, the maximum recorded lifespan of the southern subspecies of white rhinoceroses in captivity is 30 years. The expected lifespan of white rhino in captivity is 27 to 30 years, on average. However, most rhinos die unnaturally due to human poaching. Other causes of white rhinoceros death include drowning, getting stuck in mud, falling off cliffs, and burning in runaway wildfires.
|TAXONOMY||Animalia | Chordata | Mammalia | Perissodactyla | Rhinocerotidae | Ceratotherium|
Two subspecies of white rhino are recognized, the southern white rhino (SWR), (C. s. simum,) with populations in southern Africa listed as Near Threatened on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, and the northern white rhino (NWR), (C. s. cottoni,) a Critically Endangered variation nearly extinct in the wild.Based on morphological and genetic differences, estimated time since divergence from a common ancestor and phylogenetic species concepts, Colin Groves and co-workers have argued that the northern white rhino, (NWR,) should now be considered a separate species. There are a number of alternative ways to classify species and there has not been universal agreement on this issue. Groves has been criticized on a number of grounds and his recommendation has not been universally accepted. A detailed rebuttal of Groves’ proposal is also being prepared by a rhino geneticist, thus it is premature to come to a final conclusion on the issue at this time. It’s also been argued that, given conservation objectives, the issue of whether or not northern white rhino should be treated as a species or subspecies is for practical purposes somewhat academic given: 1. the high degree of relatedness of the three remaining NWRs at Ol Pejeta (calculated Founder Genome Equivalent of only 1.71); 2. the fact that any pure-bred offspring from remaining animals would be inbred; 3. the need to maximize reproductive output from all these NWR animals, (only one of which is young,) to try to retain as many adaptive NWR genes as possible by minimizing loss of genetic diversity through genetic drift; and 4. constraints to reproductive output given that the male is old and there are only two females. There can be no guarantee that a final attempt to conserve adaptive NWR genes will succeed. Inter-crossing may end up not being successful and, in due course, this would provide some support to Groves’ proposal that the NWR should be classed as a separate species.Northern white rhinos are relatively smaller in weight and body length than southern white rhinos, yet the southern subspecies has fewer body hairs than their northern counterparts. The southern race has copious, if sparse, body-hair which can easily be detected by running the hand along the animal’s back and flanks, while the northern species has a lack of body-hair. Each subspecies of white rhinoceros has a strikingly discontinuous range.
Historically, the northern white rhino used to range over parts of northwestern Uganda, southern Chad, south-western Sudan, the eastern part of Central African Republic, and north-eastern Democratic Republic of the Congo. Southern white rhinos were native to all of southern Africa, however, the current range of this subspecies is much more restricted. Sizeable southern white rhino populations occur in the African government-protected areas of greater Kruger National Park of South Africa, which incorporates additional private and state reserves, Milwane Game Sanctuary of Swaziland, Murchison Falls National Park of Uganda, Meru National Park of Kenya, and Hluhluwe-iMfolozi Park. They also occur in numerous state-protected areas and private reserves, some of which are also well protected throughout the country. There are smaller reintroduced populations within the historical range of the species in Namibia, Botswana, Zimbabwe, and Swaziland, while a small number survive in Mozambique. Populations of southern white rhino have also been introduced outside of the known former range of the subspecies to Kenya, Uganda, and to Zambia.
The southern white rhino is now the most numerous of the rhino taxa, with South Africa remaining the stronghold for this subspecies despite increased poaching.
|ETYMOLOGY||Square-Lipped Rhino/Rhinoceros, White Rhinoceros, Wide-Lipped Rhino/Rhinoceros | Ceratotherium simum|
White rhinos are so called, not because they are white, but because their faces are wide.
This mistranslation refers to the rhino’s flat, broad mouth with flat lips that allow for grazing. The lips are used to gather browse and grass, taking the place of the incisors. Their square-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.
|GEOGRAPHY||Terrestrial | Botswana, Eswatini, Kenya, Mozambique, Namibia, South Africa, Uganda, Zambia, Zimbabwe | Africa|
While Kenya has not been a white rhino range state in the last two hundred years, evidence from fossils and cave paintings in Kenya and northern Tanzania suggest that the white rhino, presumably similar to the northern race (Ceratotherium sinum cottoni,) was widespread and a part of the East African savanna fauna until 3,000 years ago or less when it was probably displaced by pastoralists who could easily kill such tame animals. This is based on the white rhino sub-fossil documented by Maeve Leakey from 3,000 year from the Lake Nakuru area of Rift Valley. Thus, at one stage, Kenya was once a white rhino range state (subspecies unknown,) and hence the white rhino as a species, but not C. s. simum as a subspecies, has probably been reintroduced to Kenya (with the latter being an introduction of a probable out of range subspecies.) A recent report of a white rhino hunting trophy from Kenya in an Austrian Museum still has to be confirmed but merits further investigation.
According to AfRSG data from 2011, the majority, 98.8%, of white rhino occur in just four countries: South Africa, Namibia, Zimbabwe and Kenya.
South Africa remains the stronghold for the southern white rhino subspecies conserving 18,800 individuals, or 93.2% of the population in 2010. Sizeable southern white rhino populations occur in the greater Kruger National Park, which incorporates additional private and state reserves, and Hluhluwe-iMfolozi Park, but also occur in numerous state-protected areas and private reserves, some of which are also well protected throughout the country.
Smaller, reintroduced populations occur within former range states in Botswana, Namibia, Swaziland, and Zimbabwe, while a small number survive in Mozambique. Populations of free-ranging southern white rhino have also been established outside their historical range in Kenya, Zambia, and more recently, Uganda, although Uganda is a former Ceratotherium simum cottoni range state. An approximately 3,500 year old white rhino subfossil indicates at one stage, Kenya was also once a white rhino range state.
In 2007, Namibia, Zimbabwe, and Kenya were the only other countries with over 300 wild southern white rhino, but following increased poaching, numbers in Zimbabwe had dropped to 290 by the end of 2010. Together, these three countries conserve 82.1% of the subspecies outside of South Africa.
The white rhino is found in subtropical and tropical shrublands and grasslands in dry, bushveld savanna habitats.
|BEHAVIOR||Social | Diurnal, Crepuscular | Not a Migrant|
White rhinos are generally sedentary and do not migrate from one place to another during different seasons. Instead, they alternately feed and rest day and night.
White rhinos are both diurnal and crepuscular, differing across seasons. During winter, white rhinos are diurnal, meaning their peak hours of activity occur during daytime. On the other hand, white rhinoceroses are crepuscular during summer seasons, with peak hours of activity between 5:00 AM and 9:00 AM and 3:00 PM to 6:30 PM. This shift is a way to avoid hotter weather in the summer, when they are least active and spend most of their time wallowing in mud baths.
The white rhino is far less excitable and dangerous to man than the black rhino (Diceros bicornis). White rhinoceroses are generally non-aggressive animals, however, females with young calves are more aggressive than males and other females because they are protective towards their calves. Although typically not aggressive, there have been a few cases in the Kruger National Park, South Africa, where white rhinos have rammed cars and scared the occupants. These aggressive behaviors of rhinoceroses are most likely caused by anthropogenic sounds that startle the rhinos. Although the white rhinoceros can injure some people, there hasn’t been any mortality associated with it.
White rhinos can run at speeds of 24 kilometers per hour, and can reach up to 40 kilometers per hour for short periods of time.
Because rhinos are mostly hairless mammals, they wallow in mud baths to protect their skin from the sun and help regulate their body temperature. They wallow most often when it’s hot. White rhinos also dust bathe in sand baths during the winter, rub and scratch themselves against objects, regularly visit salt licks, and readily enter swamps. They rarely take water baths. They can cool off by sweating, too, thereby losing moisture which they have to make up by drinking or by browsing water-rich plants.
White rhinos are nearsighted, but they have heightened senses of hearing and smell. Therefore, olfactory communications play a major role in securing their territories.
White rhinos have communal dung heaps which makes it easier for rhinos to identify each other in an area. Communal dung heaps also play a role in mating, because males can determine if a female is prepared to mate based on the smell of the dung.
White rhinos rarely share their territory with black rhinos (Diceros bicornis). Home ranges of male white rhinos are typically between 0.75 to 13.80 square kilometers, while females occupy 6 to 8 square kilometers. These rhinos tend to have greater home ranges during dry seasons because they wander more for food in dry seasons than wet seasons. The white rhinoceros has a dominance hierarchy where stronger rhinos claim more territorial space. Male white rhinoceroses actively defend a territory of about 0.7 to 3 square kilometers, on average. Female territories are slightly smaller, on average, 0.5 to 2.3 square kilometers. Dominant white rhinos have their own non-overlapping territories that they spray with urine to mark the boundaries. Males rhinos sometimes fight for their territories, but if defeated, they will often move to other territories. White rhinos only leave the territory to find water.
|DIET||Generalist | Forager | Herbivore|
White rhinos are mega-herbivores that graze on vast amount of grasses.
Their general diets include thick bush covers and short 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. They also eat fruits, as well as the leaves, stems, seeds, nuts, and flowers of trees.
|REPRODUCTION||Maternal | Polygynandrous|
Female white rhinos reach sexual maturity at the age of 3-5 years, whereas males reach sexual maturity at the age of 5-7 years. Female white rhinoceroses can reproduce from age 5-46 years. The breeding interval in white rhinos is long at 2.5-3 years. This long breeding interval is tied to a long gestational period of 530-550 days.
White rhinos give birth to one offspring at a time, which weighs, on average, 48.5 kilograms and doubles its size by 6 months. At birth, the average weight of juveniles is 40 to 60 kilograms, and the head and body length is 0.50 to 0.65 meters. The horns of juveniles can only be seen six weeks after birth, when black membranes covering the horns fall off. Body hairs are visible three months after birth. Mothers are the sole caregivers of the young and males have no parental investment on calves beyond the mating process.
White rhinoceros calves start suckling mother’s milk only hours after birth, and they usually suckle for 2 to 3 minutes at a time. White rhinoceroses start grazing at 2 months, but they are dependent on their mothers for nutrition until 6 months after birth. Beyond 6 months, the mothers still nurse their calves 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. White rhinoceros start weaning at one year and stay with their mothers for 2 to 3 years. At that time, the mothers drive their calves out of their territories and become sexually receptive again.
|Producer||Primary Consumer||Secondary Consumer||Tertiary Consumer||Apex Predator|
White rhinos are considered as keystone species because they help to increase the biodiversity of grasses and potentially prevent wildfires. The grazing of grasses by white rhinos makes grasses so short, wildfire cannot burn the grasses. It’s possible that this indirectly prevents damage to nearby towns. Furthermore, removal of rhinos from grasslands resulted in the disappearance of 50% of the land-cover of short grasses from the area.
White rhinos have a mutualistic relationship with cattle egret (Bubulcus ibis) and Cape starling (Lamprotornis nitens). These birds feed on the insects and parasites that are present in the hide and on the back of the rhinoceroses. Initially, red-billed oxpeckers (Buphagus erythrorhynchus) were also thought to have a mutualistic relationship with the rhinoceroses, however, recent studies suggested that these oxpeckers actually prolonged the healing time of wounds and removed earwax, rather than feeding and reducing ticks that are on the skin.
One of the parasites the birds feed on is ticks. There are 14 species of ticks recovered from the body of white rhinoceroses, which include Amblyomma rhinocerotis, Dermacentor rhinoceros, Hyalomma truncatum, and Rhipicephalus maculatus. Parasites such as piroplasms, which are blood-borne protozoans parasites, have been associated with the disease, such as babesiosis, in white rhinoceroses, which can be fatal sometimes. 66% of individuals of white rhinos in one study, tested exhibited infection from one species of piroplasm (Theileria bicornis). Furthermore, the infection of this parasite was not associated with age, sex, or location. The infection of these parasitic protozoans has contributed to exponential decreases of white rhinos.
White rhinos don’t have many natural predators. Some rhinos have missing parts of ear or parts of tail, due to the rare fights with spotted hyaenas (Crocuta crocuta). Furthermore, there have been a few cases where white rhinoceros calves were killed by lions (Panthera leo).
The main predator of white rhinos are humans (Homo sapiens), who illegally poach them for their horns. Although it is illegal to use white rhino horns, people obtain these horns through illegal poaching. Furthermore, the horns of white rhinos are used for medications that have no scientific validity.
To avoid potential predators, white rhinos may roam in groups consisting of females and calves. These groups are common in habitats where these large carnivores reside. A common behavior of white rhinos is the way they respond to predators, such as lion (Panthera leo) attacks. For example, all white rhinos run with their hind feet continuously striking the ground and their forefeet following the direction of the way other rhinos are running during the flight.
White rhinos are economically important for humans. Increases in ecotourism related to white rhinos have helped countries financially. For example, the prices of an average ticket to see white rhinoceroses in the Kruger National Park of South Africa has tripled in the last decade.
SPORT HUNTING/SPECIMEN COLLECTING
HANDICRAFTS, JEWELLERY, ETC.
|CONSERVATION||Population 10,080 | Not Fragmented | Decreasing | Near Threatened|
The reason for the white rhino rating as Near Threatened and not Least Concern, by the International Union for Conservation of Nature and Natural Resources (IUCN,) Red List of Threatened Species is due to the continued and increased poaching threat and increasing illegal demand for horn, increased involvement of organized international criminal syndicates in rhino poaching, as determined from increased poaching levels, intelligence gathering by wildlife investigators, increased black market prices, and apparently new nontraditional medicinal uses of rhino horn. In the absence of conservation measures, within five years, the species would quickly meet the threshold for Vulnerable if poaching rates were to further increase.
Once widespread in the bushveld areas of southern Africa, south of the Zambezi river, the southern white rhino was on the brink of extinction in 1895, having been reduced to just one small population of approximately 20-50 animals in the Umfolozi Game Reserve in KwaZulu-Natal, South Africa. However, by the end of 2010, after years of protection and many translocations, the subspecies had grown to 20,170 wild animals. On January 6, 2020, the International Union for Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Species reported the white rhinoceros population at 10,080.
Operation Rhino was launched with the first successful translocation out of Hluhluwe iMfolozi Park in 1961. Numbers of populations and rhinos have increased ever since and the result has been one of the world’s great success stories with the sub-species being successfully translocated to new areas in eight other countries and throughout South Africa. South Africa remains the stronghold for this subspecies conserving 18,800 individuals, 93.2% of the white rhino population, in 2010.
Live sales, limited sport hunting, and ecotourism have historically provided incentives which have resulted in a significant expansion of range and numbers of white rhinos on private land in South Africa, to the extent that there are now more white rhino on private land in South Africa than there are rhino in the whole of the rest of Africa. Numbers of white rhino under private ownership continue to increase, numbering at least 5,500 in 429+ populations by the end of 2010, with the majority in South Africa. The bulk of white rhino, 14,529 individuals, or 72.1% of the population, continue to be conserved on state land. As of December 2008, there were an estimated 750 in captivity worldwide.
Since 2003, poaching escalated and the population declined rapidly with 11 carcasses found in a three-month period between March and May 2004. Confirmed numbers of northern white rhino fell from 30 individuals in Garamba National Park, Democratic Republic of the Congo in April 2003 to just four in August 2005, confirmed by surveys. No live rhino have been seen since 2006 or signs of live rhino, such as spoor or dung, reported since 2007 despite intensive systematic foot surveys. It is believed that the northern white rhino has probably gone extinct in the wild. Reports of a few possible northern white rhino surviving in a remote part of Southern Sudan have yet to be confirmed although surveys are planned. The previous only confirmed population of northern white rhino in Garamba National Park in north-eastern Democratic Republic of the Congo is now considered probably extinct. Despite systematic ground surveys over probable range and additional foot patrols and aerial reconnaissance, no live rhinos have been seen since 2006 and no fresh sign since 2007. There have been unconfirmed reports of rhino in southern Sudan, and surveys are planned. The last three potential breeding northern white rhino in captivity in Dvur Kralove Zoo in the Czech Republic have been translocated to a private conservancy in Kenya in the hope this will stimulate their breeding. These animals form the only current confirmed population.
One of the main threats to the white rhino population is illegal hunting, or poaching, for the international rhino horn trade. Vietnam is the top destination for South African rhino horn and fails on compliance and enforcement. Rhino horn has two main uses: traditional use in Chinese medicine, and ornamental use. A new, non-traditional use of rhino horn is to supposedly treat cancer, although there is no supporting clinical evidence of its effectiveness. For decorational purposes, rhino horn is a highly prized material for making ornately carved handles for ceremonial daggers, called jambiyas, worn in some Middle East countries. Rhino horns are poached from animals in the wild and, in some cases, stolen or illegally sold from horn stockpiles, private trophies, and museum exhibits. In recent years, poaching levels have increased in major range states South Africa, Zimbabwe, and Kenya. Swaziland also recently lost its first rhino to poaching since December 1992. Psuedohunting where sport hunting has been undertaken by individuals from non-traditional hunting countries, has also probably been responsible for some of the illegal horn getting onto the market.
Poaching and civil wars in both the Democratic Republic of the Congo and neighboring Sudan have had a devastating impact on northern white rhino, Ceratotherium simum cottoni. Whilst poaching pressure initially increased during civil unrest and war in the late 1990s, good reproduction enabled the population to remain relatively stable. Numbers were believed to have stood at around 2,360 in 1960.
Until recently, poaching of white rhinos has not had a serious impact on overall population numbers, with poaching losses being surpassed by encouraging growth rates. The annual average poaching incidents during 2003 to 2005 represented just 0.2% of the total number of white rhinos at the end of 2005. However, poaching levels have increased dramatically in recent years in major range states South Africa, Zimbabwe, and Kenya in response to significant increases in black market prices for horn. Swaziland also recently lost its first rhino to poaching since December 1992. For example, the total numbers of rhinos poached annually in the major range state, South Africa, has increased from 13, to 83, 122, 333, and 480 over the period 2007-2011. 232 individuals were arrested for poaching activities in 2011. While still less than the net growth in numbers, due to breeding, the continued escalation in poaching threatens to soon reverse the gains achieved. If current trends continue, numbers in South Africa could start to decline.
As a proportion of total numbers, poaching levels in the major range states have been highest in Zimbabwe.
The significantly increased and escalating poaching, increased protection costs, declining live sale prices and reduced incentives are leading to increasing numbers of private owners in South Africa seeking to get rid of their rhino. If this worrying trend continues, this threatens to reverse the expansion of range and has the potential to also significantly reduce conservation budgets due to declining live sales.
Effective field protection of white rhino populations is critical. Current successful protection efforts of the white rhino have depended on significant range state expenditure and effort, and if these were to decline, especially in South Africa, rampant poaching could seriously threaten numbers, well in excess of 30% over three generations.
Declining state budgets for conservation, declining capacity in some areas, and increasing involvement of Southeast Asians in African range states are all of concern.
Many remaining rhino are now concentrated in fenced sanctuaries, conservancies, rhino conservation areas, and intensive protection zones where law enforcement effort can be concentrated at effective levels. Monitoring has also provided information to guide biological management decision-making aimed at managing rhino populations for rapid population growth. This has resulted in surplus animals being translocated to set up new populations both within and outside the species’ former ranger.
Increasing efforts are also being made to integrate local communities into conservation efforts. Strategically, white rhinos are now managed by a range of different stakeholders, private sector and state, in a number of countries increasing their long-term security. In Southern Africa, live sale of white rhinos on auction and limited sport hunting of surplus males has also created incentives for private sector conservation and generated much needed funds which can help pay the high cost of successfully monitoring, protecting, and managing rhino. However, incentives are declining while protection costs and risks have increased, resulting in increased numbers of South African owners looking to get rid of their white rhino.
The last three potential breeding northern white rhino in captivity were moved to a private conservancy in Kenya in the hope that a move to more wild conditions would stimulate them to breed. Conservation biologists, Bob Lacy and Kathy Traylor-Holzer, have advised that given the current situation of the northern white rhinoceros and overall conservation objective, a stage has been reached where one doesn’t really have any choice of achieving medium to longer term conservation goals without trying inter-crossing the northern white rhino with southern white rhino so as to preserve some northern genes within breeding populations that can hopefully later resume evolutionary adaptation to wild habitats. They have advised that even in the total absence of human-caused losses, such as poaching, genetic and demographic modelling of such a small population of inter-related animals shows that the remaining three northern white rhinoceroses are unlikely on their own to form a viable population in the longer term because of the negative effects of the severe inbreeding that would most likely occur, and the high probability of chance demographic events significantly reducing or eliminating the remnant population at some time before it has a chance to grow to safer numbers. Thus, attempts at only pure breeding of the northern white rhino, alone, under these circumstances seem very likely to fail in the medium to longer term, and are, at best, might only be able to preserve inbred museum specimens that would not appropriately represent the original northern white rhino. There can be no guarantee that this last-ditch attempt to conserve adaptive northern white rhino genes will succeed and inter-crossing may end up not being successful.
INVASIVE & OTHER PROBLEMATIC SPECIES, GENES, & DISESASES
CLIMATE CHANGE & SEVERE WEATHER