Scientific Name:

Ceratotherium simum (Burchell 1817)

Description:

As the white rhino evolved from the black rhino they are similar in appearance. White rhinos have broad, flat lips 20 cm wide for grazing and the head cannot be lifted above the back. The upward swivel of the head is prevented by the first neck vertebra, which has an elongated upper anterior end that interlocks with the skull bone. 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. Recent rhinos have only six molars. Adult white rhinos have an average shoulder height of 165-175 cm and a maximum mass of 2 400 kg. Bulls are 30% larger than cows; this differs from the black rhino where the cows are the largest. 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.  Both sexes have two asymmetrical horns. The horns do not have a bone core and consist of a compact mass of tubular keratin fibres growing directly from the skin. The horns of adult bulls are thicker around the base and have a larger circumference than those of the cows. 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 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. The anterior horn becomes visible at five weeks and measures approximately 4 cm at three months and 10 cm at seven 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. If the horn is lost or harvested, re-growth immediately accelerates to 10-11 cm per annum for the first two years, independent of the age of the animal and then rapidly declines.

Habitat:

White rhino habitat is restricted to areas with an annual rainfall of between 250-800 mm and access to open drinking water at ground level. Veld on a substrate of dolerite and shale is preferred, on granite substrate is marginal and on sandstone is unsuitable and avoided.  
White rhinos are highly attracted by the new grass growth on burnt veld and are usually the first animals to move onto it. Moderate to dry savannahs are the most suitable habitat and should have a herbaceous layer of sweet, short, grass species 5-25 cm high, surface drinking water, mud holes for baths, patches of dense thicket for refuge, scattered tree foliage for shade and resting and a relatively flat terrain with slopes <20°. Pure sour veld is unsuitable, and steep slopes, ridges and mountains, rocky surfaces and forests are totally avoided. Open grassy plains with few trees are marginal to unsuitable for white rhino, as is a dense layer of knee-high shrubs in the grass layer, as this hinders grazing.

Distribution:

In the past, the white rhino lived in an area stretching from Morocco, across the western Sahara and the Sahel, to the eastern, central and southern areas of Africa. More recently, a gap approximately 2 000 km wide appeared between the northern and southern sub-populations. This gap, situated between Uganda and north-western Kenya, contributed to the genetic diversion of the two present subspecies and coincided with the global climatic changes between the humid and dry periods that affected the expansion and retreat of the African forest zones. Scientific findings indicate that tropical forests may have stretched from the Cape to Ethiopia during the summit of the last glacial period around 14 000 to 12 000 years BP. Such conditions would render the central area of Africa unsuitable for white rhino and explain the distribution gap.
By 1904, the southern white rhino population was approaching extinction, the last ten remaining individuals surviving in the Umfolozi Game Reserve. By 1929, conservation measures had restored their numbers to 150, by 1960 to 700 and by 1970 to 2000. During the late 1960s and the 1970s, several southern white rhinos were relocated to other African countries, such as Kenya, the Ivory Coast, Namibia and Zimbabwe. It is presently listed by the IUCN as Near Threatened. The northern white rhino was declared critically endangered in 2005, when its number stood at 28 in a park in the north of the Democratic Republic of the Congo.

Size and weight:

Adult white rhinos have an average shoulder height of 165-175 cm and a maximum mass of 2 400 kg. Bulls are 30% larger than cows; this differs from the black rhino where the cows are the largest. The skin is up to 20 mm thick on the back and thighs and up to 50 mm on the

Lifespan:

35 to 40 years