Southern white rhinoceros

Southern white rhinoceros
A Southern white rhinoceros at Kruger National Park, South Africa.
Conservation status
Near Threatened  (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Perissodactyla
Family:	Rhinocerotidae
Genus:	Ceratotherium
Species:	C. simum
Subspecies:	C. s. simum
Trinomial name
Ceratotherium simum simum (Burchell, 1817)
Range map in green
Synonyms
Ceratotherium simum burchellii (Desmarest, 1822) Ceratotherium simum oswellii ((Elliot, 1847) Ceratotherium simum kiaboaba (Murray, 1866)

The Southern white rhinoceros or southern square-lipped rhinoceros (Ceratotherium simum simum), is one of the two subspecies of the white rhinoceros. It is the most common and widespread species of the rhinoceros.

As of late December 2007, the total population was estimated at 17,460 southern white rhino in the wild, making them by far the most abundant subspecies of rhino in the world. South Africa is the stronghold for this subspecies (93.0%), conserving 16,255 individuals in the wild in 2007. However, the current census from Save the Rhino's official website revealed there are 20,405 southern white rhinoceros since 2013.

Taxonomic and evolutionary history

The southern white rhinoceros is the nominate subspecies, which was given the scientific name Ceratotherium simum simum by the English explorer William John Burchell in the 1810s. Other names were also proposed for the southern subspecies. The subspecies is also known as Burchell's rhinoceros (Ceratotherium simum burchellii) and Oswell's rhinoceros (Ceratotherium simum oswellii). However, they are considered as synonyms to its original scientific name.

Ceratotherium simum kiaboaba (or Rhinoceros kiaboaba), also known as straight-horned rhinoceros, was proposed as a different variety found near Lake Ngami and north of the Kalahari desert. However, it was discovered to be an actual southern white rhinoceros.

Following the phylogenetic species concept, recent research in 2010 has suggested the southern and northern white rhinoceros may be different species, rather than subspecies of white rhinos, in which case the correct scientific name for the northern subspecies is Ceratotherium cottoni, and the latter should by known as simply Ceratotherium simum. Distinct morphological and genetic differences suggest the two proposed species have been separated for at least a million years.

Physical descriptions

A southern white rhino mother with calf in Namibia.

The southern white rhinoceros is one of largest and heaviest land animals in the world. It has an immense body and large head, a short neck and broad chest. Females weigh 1,600 kg (4,000 lb) and males 2,400 kg (5,000 lb). the head-and-body length is 3.5–4.6 m (11–15 ft) and a shoulder height of 1.8–2 m (5.9–6.6 ft). On its snout it has two horns. The front horn is larger than the other horn and averages 90 cm (35 in) in length and can reach 150 cm (59 in). Females usually have longer but thinner horns than the males which is larger but shorter. The southern white rhinoceros also has a prominent muscular hump that supports its relatively large head. The colour of this animal can range from yellowish brown to slate grey. Most of its body hair is found on the ear fringes and tail bristles, with the rest distributed rather sparsely over the rest of the body. Southern white rhinos have the distinctive flat broad mouth that is used for grazing.

Habitat and distribution

A southern white rhino pair at Mosi-oa-Tunya National Park, Zambia.

The southern white rhino live in the grasslands and savannahs of southern Africa, ranging from South Africa to Zambia. About 98.5% of southern white rhino occur in just five countries (South Africa, Namibia, Zimbabwe, Kenya and Uganda). The southern white rhino was the most endangered species. The species was nearly extinct with just less than 20 individuals in a single South African reserve in early 20th century. Fortunately, the small population of white rhinoceros has slowly recovered during the years, having grown to 840 individuals back in 1960s to 1000 in the 1980s. However, at 1968, the white rhino trophy hunt has been legalized which threatened the endangered species.

Almost at the edge of extinction in the 20th century, the southern white rhinoceros has made a tremendous comeback. In 2001, it was estimated that there were 11,670 white rhinos in the wild of southern Africa with a further 777 individuals in captivity worldwide, making it the most common rhinoceros in the world. By the end of 2007, wild-living southern white rhino had increased to an estimated 17,480 animals. In 2013, there are an estimated population of 20,405 wild southern white rhinoceros.

Threats

The southern white rhinoceros is listed as Near Threatened, though it is mostly threatened by habitat loss, continuous poaching in recent years and the high illegal demand for rhino horn for commercial purposes and the traditional Chinese medicine.

Conservation status

Introduction/Reintroduction projects

A southern white rhinoceros herd in Lake Nakuru, Kenya.

A captive southern white rhinoceros in Bioparc Valencia, Valencia, Spain.

There are smaller reintroduced populations within the historical range of the southern white rhinoceros in Namibia, Botswana, Zimbabwe, Swaziland, Zambia and in southern Democratic Republic of the Congo, while a small population survives in Mozambique. Populations have also been introduced outside of the former range of the species to Kenya, Uganda and Zambia, where their northernmost relatives used to occur. The southern white rhinoceros have been reintroduced in the Ziwa Rhino Sanctuary, the Murchison Falls National Park in Uganda and in the Lake Nakuru National Park in Kenya.

In 2010, nine southern white rhinoceros were imported from South Africa and shipped to the Yunnan province from southeast China where they were kept in an animal wildlife park for acclimation. In March 2013, seven of the animals were shipped to the Laiyanghe National Forest Park, a habitat where Sumatran and Javan rhinoceros once lived. Two of the southern white rhinos began the process of being released into the wild on May 13, 2014.

In captivity

Wild-caught southern white rhinoceros will readily breed in captivity given appropriate amounts of space and food, as well as the presence of other female rhinos of breeding age. For instance, 93 calves have been born at the San Diego Zoo Safari Park since 1972. However, for reasons that are not currently understood, the rate of reproduction is extremely low among captive-born southern white females.