White / Square-lipped Rhinoceros
Ceratotherium simum (Burchell 1817)
Photo: Doug Lee
IUCN Conservation Status:
- The Southern white rhino is NT = Near Threatened
- The Northern white rhino is CE = Critically Endangered
After the elephant the white rhino is the largest land mammal on earth
today. It evolved from the black rhino in relatively recent historical
times and spread in large numbers over Africa, Eurasia and North
America. However mans greed took its toll on the populations, and by
1904 only 10 southern white rhinos still survived, and by 1988 only 17
northern white rhinos. Conservation initiatives have restored the
numbers of the southern white subspecies and the total population now
exceeds 13 000 animals. Although the white rhino may have earned its
name by rolling in white mud it is also possible that the name was an
early mistranslation of the Dutch word “wijd” which refers to its wide
mouth. The generic name “Ceratotherium” is derived from the Greek terms
keras "horn" and therion "beast".
|Order:||PERRISSODACTYLA (Odd toed)|
Four genera with five extant species and six subspecies are recognized:
- Rhinoceros the single-horned rhinoceros with two species
- R. unicornis the Indian rhinoceros
- R. sondaicus the Javan rhinoceros
- Dicerohinus the two or double-horned Sumatran rhinoceros Dicerohinus sumatrensis
- Ceratotherium the white or square-lipped rhinoceros with two subspecies
- C. simum simum the southern white rhinoceros
- C.s. cottoni the northern white rhinoceros
- Diceros the hook-lipped or black rhinoceros with six subspecies
- D. bicornis longipes the West African black rhinoceros
- D.b. brucii the north-eastern black rhinoceros
- D.b. michaeli the East African black rhinoceros
- D.b. bicornis the Cape or black rhinoceros
- D.b. minor the southern black rhinoceros
- D.b. chobiensis the south-western black rhinoceros
Diceros praecox, from
which the black rhino originated, evolved 14 million years BP in Europe
and arrived in Africa between 11and 8 million years BP. The ancestors
of the white rhinoceros diverged from a black rhinoceros ancestor in
Africa during the early Pliocene about 5-4 million years BP. The black
and white rhinos remain so closely related that inter-specific
hybridization has been confirmed by Robinson et al (2005). A
reproductive hybrid of the northern and southern white rhinoceros
subspecies was bred in the Dvur Kralové Zoo in the Czech Republic in
The most southern record of white rhino is a skeleton exposed by
workers digging the foundations for the Grassridge Dam between Hofmeyr
and Middelburg in the Eastern Cape. At present the distribution of
rhino in Africa is limited to protected parks and private game farms.
Click here to view more photographs.
As the white rhino
evolved from the black rhino they are similar in appearance. The main
differences between white and black rhino lie in the neck and the shape
of the mouth. White rhinos have broad, flat lips 20 cm wide for grazing
and the head cannot be lifted above the back. Bulls are 30% larger than
cows. The body colour bears no relation to the names “white” and
“black” as rhinos are fond of rolling in mud baths and the body takes
on the colour of the soil. The skin is up to 20 mm thick on the back
and thighs and up to 50 mm on the forehead.
There are minor differences between the southern and northern white
rhino subspecies. The latter has a shorter body and legs. The skin of
the southern form contains hard, pin-like, sparsely scattered hairs
that are absent in the northern form. The dorsal side of the skull of
the northern sub-species is flatter than that of the southern and the
molars have smaller crowns.
Comparison To Man
Both sexes have two
asymmetrical horns, the larger horn is situated on the end of the
muzzle just behind the nostrils and the second, smaller horn halfway up
the nose between the first horn and the forehead. The horns do not have
a bone core and consist of a compact mass of tubular keratin fibres
growing directly from the skin. Cow horns, although thinner, are
generally longer than those of a bull. The mean, accumulative mass of
both horns of adult white rhinos ranges from 5.8-14.0 kg. The mass of
the anterior horn ranges from 0.29-11.04 kg, and the posterior horn
from 0.01-4.0 kg. The mean horn growth rate of calves is 15 cm during
the first year, declining to 5.6-6.4 cm per annum in young adults aged
8-25 years and 2.7-4.5 cm in adults of 25 years and older (Pienaar et
al 1991). The anterior horn becomes visible at five weeks and measures
approximately 4 cm at 3 months and 10 cm at 7 months. Rhinos,
especially bulls, frequently rub their horns against tree trunks and
rocks causing the horn tip to wear away. This rapidly reduces the
growth to a maximum trophy length of about 120 cm at a prime age of
28-30 years, after which it is further reduced to a maximum of 100 cm
at 40 years age.
Moderate to dry savannahs are the most suitable habitat and should meet the following basic parameters
- a herbaceous layer of sweet, short, grass species 5-25 cm high
- surface drinking water
- mud holes for baths
- patches of dense thicket vegetation for refuge
- scattered tree foliage for shade and resting
- relatively flat terrain with slopes <20°.
Temperate grasslands, the
moist, sour grasslands of the highveld and montane regions, or moist
forest-like environments, are totally avoided. Veld on a substrate of
dolerite and shale is preferred, on a granite substrate is marginal and
on sandstone is unsuitable and avoided. A habitat of mixed sweet and
sour grasses is marginal while pure sour veld is unsuitable. White
rhinos are highly attracted by the new grass growth on burnt veld and
are usually the first animals to move onto it.
Feeding & Nutrition
White rhino are partly selective, roughage grazers. They feed
predominantly on short, sweet, palatable grasses and do not ruminate as
they are monogastric. Care should be taken when supplying supplementary
food concentrates as rhino, together with zebra, cannot tolerate the
high levels of urea found in some brands. When grazing is poor, rhino
do well on supplementary dry lucerne and horse cubes but these
supplements should not exceed 10% of the daily dietary intake. White
rhinos are dependant on water and drink up to 50 litres at a time with
an average water consumption of 12 litres per day. The bulk of their
feeding usually takes place during the morning and from late afternoon
into the evening. The daily food intake for an adult is 50-65 kg and
when confined to a boma, 35-40 kg.
White rhino are
semi-social and stay in small breeding groups of one adult cow older
than 5 years, her calf of younger than 2.5 years and 1-3 sub-adult cows
of 3-5 years. An adult bull often accompanies the group for mating
purposes, an association that rarely lasts more than 7-8 days.
Sub-adults of both sexes form mixed groups of 3-5 individuals, while
adult bulls are mostly solitary and territorial. Bull calves leave the
breeding group at 2.5-3.5 years after the birth of the next calf and
join sub-adult groups until they reach social maturity. Temporary
aggregations of 2-3 groups are often found at water holes, at
centralized feeding grounds during drought and in bad seasons. The
natural population structure is 19% adult bulls, 26% adult cows, 32%
sub-adults and 23% calves. Due to the long calving interval, a maximum
of 40% of the adult cows, or 10.4% of the population calve per annum.
|Southern white rhino information table
|Adult body weight
|Adult shoulder height
|Age of sexual maturity
|Age of social adulthood (1st mating)
|1st calf born at
|Post maturity age (last mating)
|Year round (peak Mar-Apr)
|Gender ratio: Natural (all ages)
|Gender ratio: Production (all ages)
|Mating ratio: Natural (adults)
|Mating ratio: Production (adults)
Absolute minimum number needed
Smallest viable population size
|Spatial behaviour: Home range
|Spatial behaviour: Territory range
|Large stock grazing unit (adult):
Dietary ratio (grass):
4.5 per animal
(99% of diet)
|3.7 per animal
(99% of diet)
|Browsing unit (adult):
Dietary ratio: (browse):
|6.6 per animal
(1% of diet)
|5.9 per animal
(1% of diet)
|Maximum stocking load
|4 animals per 1000 ha
(at 400mm annual rainfall)
|Minimum habitat size required
|Annual population growth
|Optimal annual rainfall
|Optimal vegetation structure:
Woody canopy cover:
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