Historically, northwestern Uganda, southern Chad, south-western Sudan, the eastern part of center African Republic, and northeastern Democratic Republic of the Congo were the native places for northern white rhinoceroses (Ceratotherium simum cottoni). Southern white rhinoceroses (Ceratotherium simum simum) were native to all of southern Africa. However, the current range of these subspecies is much more restricted. Presently, northern white rhinoceroses only inhabit the Democratic Republic of the Congo. Whereas, the southern white rhinoceroses inhabit Botswana, Namibia, Swaziland, Zimbabwe, Ivory Coast, Kenya, and Zambia. Furthermore, 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. ("African rhino. Status survey and conservation action plan", 1999; Estes, 1991; Groves, 1972; Nowak, 1999; Skinner and Chimimba, 2006)
Typical habitat for white rhinocerose includes dense forests, savannas, and woodlands with grassy openings. White rhinoceroses usually live near water sources because they generally consume water as often as twice a day. In addition, white rhinoceroses are more commonly found near riverbanks and bottomland areas during morning hours. As temperature increases, they move to shadier areas such as dense forest or mid-slopes of hills. (Estes, 1991; Groves, 1972; Nowak, 1999)
White rhinoceroses are one of the largest terrestrial mammals. They weigh approximately 1000 to 3600 kg as adults. White rhinoceroses have relatively small eyes compared to their body size, squared-shaped lips, and a long neck with a hump. They have two horns of unequal size. The recorded length of longer horns is 1660 mm in length. These are longer and thinner in females. The shorter horns can grow up to 550 mm in length.
The average length of their head and body, not including tail, is 3.35 to 3.77 m. The average length of tail of white rhinoceroses ranges from 0.57 to 0.77 m. In addition, white rhinoceros average shoulder height is 1.71 to 2.85 m, whereas their average girth is between 2.01 and 2.20 m. These animals have 24 teeth, with a dental formula of: incisors 0/0, canines 0/0, premolars 3/3, and molars 3/3.
White rhinoceroses have pale gray skin which is dense, tough, and has plate-like folds. The epidermis of white rhinoceroses is 1 mm thick and their dermis is 18 mm thick, on average. White rhinoceroses have hypsodont teeth. Moreover, they have flat broad mouth for grazing. White rhinos are so called not because they are "white," but because their face is "wide" (a missed translation).
At birth, the average weight of juveniles is 40 to 60 kg, and the head and body length is 0.50 to 0.65 m. 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 of birth in white rhinoceroses.
Northern white rhinoceroses (Ceratotherium simum cottoni) are relatively smaller in weight and body length than southern white rhinoceroses (Ceratotherium simum simum). In both subspecies, female white rhinoceroses are slightly smaller than males. However, there is no quantitative data published on the sizes of males and females and northern and southern to compare here. A feature that distinguishes these two subspecies from each other is their body hairs, as the southern subspecies has fewer body hairs than their northern counterparts. (Estes, 1991; Groves, 1972; Nowak, 1999; Pienaar, 1994a)
The mating system in white rhinoceroses is polygynandrous, meaning both males and females have multiple sexual partners. Male white rhinoceroses are vigilant for females who enter into their territory. Once the female enters the territory, the male remains with the female for a day to investigate whether the female is ready to mate. If the female is ready, then the male usually follows her for 3 to 5 more days, during which time the females responds with snorts and roars. Before mating, pair bonds last for 5 to 20 days; in this period if females attempt to enter another male’s territory, males block the way, and sometimes confrontation occurs between males and females. However, if females successfully enter into another male's territory, then the previous male will discontinue his effort to follow the femal.
Males detect whether females are ready to mate by the smell of urine; urine includes chemicals that signals females in estrus. Females usually experience their first estrus at the age of three and half years, but they don’t breed until age 5. Almost all females breed after 5 years of age. Some of the signs of mating behaviors sent by female rhinoceroses are frequent urination and whistling sounds. Among males of the same population, fecal testosterone levels in territorial males are higher than the non-territorial males. Furthermore, territorial males usually spend more time with females and generally have more mating partners than non-territorial males. Thus, territorial males have higher reproductive success than non-territorial males.
While mating, male white rhinoceroses place both of their feet on the back of the female. Copulation lasts for 15 to 30 minutes on average, with ejaculations every 4 to 5 minutes. Mating behavior continues for 2 to 5 days as testosterone levels of male are high for 2 to 5 days. After that, the female leaves the male’s territory. (Estes, 1991; Groves, 1972; Nowak, 1999; Pienaar, 1994a; Rachlow, et al., 1998)
White rhinoceroses breed throughout the year, but breeding usually peaks between October to December in southern African populations and February to June in eastern African populations. 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. (Estes, 1991; Groves, 1972; Nowak, 1999; Pienaar, 1994a; Rachlow, et al., 1998)
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. White rhinoceros stay with their mother for 2.5 to 3 years. At that time, the mothers drive their calves out of their territories and become sexually receptive again. (Estes, 1991; Groves, 1972; Nowak, 1999; Pienaar, 1994a; Rachlow, et al., 1998)
The lifespan of white rhinoceroses differs between captivity and in the wild. The average lifespan of both males and females in the wild is 46 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 rhinoceroses in the wild is between 39 to 43 years and 27 to 30 years in captivity, on average. However, most rhinoceroses 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. (Groves, 1972; Carey and Judge, 2000; Estes, 1991; Groves, 1972; Nowak, 1999; Rachlow, 1997; Weigl and Jones, 2005)
A common behavior of white rhinoceroses is the way they respond to predators, such as lion (Panthera leo) attacks. For example, all white rhinoceroses 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 rhinoceroses can run at speeds of 24 km/hr, and can reach up to 40 km/hr for short periods of time. White rhinoceroses are generally non-aggressive animals. However, females with young calves are more aggressive than the males and other females because they are protective towards their calves. Other common behaviors include the use of mud baths during summer and sand bath during winter. White rhinoceroses rarely take water baths. White rhinoceroses are both diurnal and crepuscular and this differs across seasons. During winter, they are diurnal, meaning their peak hours of activities time occur during daytime. On the other hand, white rhinoceroses are crepuscular during summer seasons, with peak hours of activities are between 5 AM to 9 AM and 3 PM to 6:30 PM. This shift is a way to avoid hotter weather in the summer. White rhinoceroses do not migrate from one place to another during different seasons. Males rhinoceroses sometimes fight for the territory. Defeated males often move to some other territory. Furthermore, males urinate to determine the boundaries and they leave the territory only when going to get water. White rhinoceroses rarely share the territory with the other rhinoceroses. (Estes, 1991; Groves, 1972; Rachlow, et al., 1998)
Dominant white rhinoceroses have their own non-overlapping territories. Home ranges of male rhinoceroses are typically between 0.75 to 13.80 square kilometers, while females occupy 6 to 8 square kilometers The white rhinoceroses have dominance hierarchy, where stronger rhinoceroses 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. These rhinoceroses tend to have greater home ranges during dry seasons because they wander more for food in dry seasons than wet seasons. (Estes, 1991; Groves, 1972; Nowak, 1999; Pienaar, 1994a; Pienaar, 1994b)
White rhinoceroses communicate using several different noises. Typically, male white rhinoceroses are louder than females. In addition, during fights with other bulls, males make grunts and snorts. Females utter a loud bass bellow while fighting with other females or in confrontation with males. Panting, whining, and squeaking are the sounds made by calves if they do not see their mother. White rhinoceroses often make gruff squeaking sounds when chasing or being chased, and their defensive sound is snarling. Male rhinoceroses make hic-throbbing sounds when approaching females.
White rhinoceroses are nearsighted, but they have heightened senses of hearing and smell. Therefore, olfactory communications play an major role in securing their territories. In white rhinoceros populations, dominant males spray their urine to mark the boundaries of their territories. Furthermore, white rhinoceroses have communal dung heaps, which makes it easier for rhinoceroses 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. (Estes, 1991; Groves, 1972; Nowak, 1999; Skinner and Chimimba, 2006)
White rhinoceroses are strictly herbivores. 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. 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. White rhinoceros newborn calves drink only mother’s milk for two to three week after birth. After two weeks, mothers teach their newborns to eat soft and juicy grasses and other vegetation. White rhinoceroses drink their mother’ milk up to 18 months post-natally, start eating regular diets, like their mothers, after four to five months. (Estes, 1991; Groves, 1972; Nowak, 1999; Skinner and Chimimba, 2006)
White rhinoceroses don’t have many natural predators. Some rhinoceroses have missing parts of ear or parts of tail, due to the rare fights with hyenas (Crocuta crocuta). Furthermore, there have been a few cases where white rhinoceros calves were killed by lions (Panthera leo). To avoid these potential predators, rhinoceroses may roam in groups consisting of females and calves. These groups are common in habitats where these large carnivores reside. The main predator of white rhinoceroses are humans (Home sapiens), who illegally poach them for their horns. (Estes, 1991; Ferreira, et al., 2015; Groves, 1972; Nowak, 1999; Skinner and Chimimba, 2006)
White rhinoceroses are mega-herbivores that graze on vast amount of grasses. White rhinoceroses also are considered as keystone species because they help to increase the biodiversity of grasses and potentially prevent the wildfires. Waldram et al. (2008) reported that the grazing of grasses by white rhinoceroses makes grasses so short, wildfire cannot burn the grasses. Furthermore, removal of rhinoceroses from grasslands resulted in the disappearance of 50% of the landcover of short grasses from the area.
In addition, white rhinoceroses have 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 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 that bird 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. Otiende et al. (2015) found that 66% of individuals of white rhinoceroses 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 rhinoceroses. (Govender, et al., 2011; Groves, 1972; Otiende, et al., 2015; Penzhorn, et al., 1994; Waldram, et al., 2008)
White rhinoceroses are economically important for humans. Increases in ecotourism related to white rhinoceroses 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. Although it is illegal to use white rhinoceroses’ horns, people obtain these horns through illegal poaching. Furthermore, the horns of white rhinoceroses are used for medications that have no scientific validity.
In addition, rhinos are known to reduce the chance of wildfire because of their grazing habits. It’s possible that they indirectly prevent damage to nearby towns. (Rachlow and Berger, 1997; Saayman and Merwe, 2003)
Although typically not aggressive, there have been a few cases in the Kruger National Park, South Africa, where rhinoceroses have rammed the cars and scared the occupants. These aggressive behaviors of rhinoceroses are most likely caused by anthropogenic sounds that startle the rhinos. Although white rhinoceroses can injure some people, there hasn’t been any mortality associated with it. (Durrheim and Leggat, 1999)
The IUCN Red List states that the northern white rhinoceroses are “Critically Endangered” species and they are possibly extinct in the wild. According to IUCN Red List, northern white rhinoceroses have not been seen in the wild since 2006 and only four remain in the captivity. Southern white rhinoceroses are described as “Near Threatened” on the IUCN Red List. Northern white rhinoceroses are listed in Appendix I of CITES, which means they are most endangered species and any international trade or any commercial uses are prohibited. Southern white rhinoceroses are classified into Appendix II on CITES. Appendix II states that the species are not threatened with extinction, but monitoring trade is necessary for species' numbers to be sustainable. Furthermore, the US Federal List has listed southern white rhinoceroses as “Threatened” and northern white rhinoceroses as “Endangered.” The state of Michigan list does not contain any special status of both species of white rhinoceroses.
Initially, southern white rhinoceroses were thought to be extinct by 1880. However, the discovery of four southern white rhinoceroses in Zululand, present-day South Africa, in 1883, proved that southern white rhinoceroses were not extinct but a critically endangered species. Since the 1950s, conservation practices have been applied, along with strong conservation laws passed by governments. However, the situation worsened after internal conflicts and civil wars arose in some African countries, which drastically decreased the white rhinoceroses’ population during late 1970s and 1980s. To conserve these rhinoceroses, individuals were relocated to different parks, such as Kruger National Park, South Africa. Relocation of southern white rhinoceroses has been extremely successful, as numbers grew from 337 to 1876 in the span of 20 years (1973 to 1993). Today, there are more than 15,000 southern white rhinoceroses in the world.
On the other hand, northern white rhinoceroses never recovered from poaching by humans. Northern white rhinoceroses inhabit in the poor and undeveloped northern countries of Africa, such as Sudan, Chad, and Uganda. As a result of weak regulations and weak centralized governments, poaching of northern white rhinoceroses has intensified. The numbers of northern white rhinoceroses decreased from 500 in 1968 to four in 2015. These four northern white rhinoceroses are in captivity and it has been hypothesized that there are not any northern white rhinoceroses left in the wild.
White rhinoceroses’ populations have declined because of illegal poaching by humans for horns. These horns are made of keratin and are not useful for any kind of medications. However, people, mostly from China and eastern Asia, still use the horns for their traditional medication, which science considers pseudo-medicine. In attempt to preserve rhinoceroses, CITES, in 1977, banned international trades of all rhinoceroses. Despite the effort by CITES, the illegal killing and trading of rhinoceroses continued. The failure of CITES to limit trade gave rise to the new trade regulations, like Resolution Conf 6.10, made by the United Nations. This resolution, made in 1981, prohibited any international/national sale or trade of the rhinoceroses’ horn and skin. The resolution also encouraged that governments destroy the stocks of rhinoceros horns. However, countries such as South Africa, Zimbabwe and Namibia opposed the international ban on trades of rhinoceroses’ products because these countries had horns of rhinoceroses that were collected by arresting the poachers.
In 1994, the United States threatened to ban the trade of any wildlife and fisheries with the countries that did not follow the international trade bans. In response to the U.S. threat, countries such as South Africa, Zimbabwe, and Namibia explored alternate approaches to conserving rhinoceroses, so that they could continue international trade. The conservation practices applied by these countries were “dethroning” the horns of rhinoceroses (preemptively cutting off the horns, at no immediate harm to the individuals) and erecting fencing. Fences around the forest where rhinoceroses reside, plus armed guards, has been an effective conservation practice. Furthermore, safe dethroning techniques have reduced poaching efforts. (Ferreira, et al., 2015; Groves, 1972; Rachlow and Berger, 1997; Rachlow, 1997; Sara, 2003)
Dharmindra Dulal (author), Radford University, Karen Powers (editor), Radford University, Alex Atwood (editor), Radford University, Marisa Dameron (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
uses sound to communicate
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
uses smells or other chemicals to communicate
active at dawn and dusk
ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates
humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
parental care is carried out by females
an animal that mainly eats leaves.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly plants or parts of plants.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter).
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
chemicals released into air or water that are detected by and responded to by other animals of the same species
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
scrub forests develop in areas that experience dry seasons.
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
The term is used in the 1994 IUCN Red List of Threatened Animals to refer collectively to species categorized as Endangered (E), Vulnerable (V), Rare (R), Indeterminate (I), or Insufficiently Known (K) and in the 1996 IUCN Red List of Threatened Animals to refer collectively to species categorized as Critically Endangered (CR), Endangered (EN), or Vulnerable (VU).
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
movements of a hard surface that are produced by animals as signals to others
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
breeding takes place throughout the year
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