White Rhinoceros
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[Photo] A mother White rhino and her several year old daughter grazing in Matobo National Park, Zimbabwe. auteur : philipn. There are no usage restrictions for this photo. Source: http://sxc.hu/browse.phtml?f=view&id=325845
The White Rhinoceros or Square-lipped rhinoceros (Ceratotherium simum) is one of the five species of rhinoceros that still exists and is one of the few megafauna species left. Behind the elephant, it is probably the most massive remaining land animal in the world, along with the Indian Rhinoceros which is similar in size. It is well known for its wide mouth used for grazing and for being the most social of all rhino species. The White Rhino is the most common of all rhinos and consists of two subspecies, with the northern subspecies being rarer than the southern.
Subspecies
Southern white rhinoceros
There are two subspecies of White Rhinos; as of 2005, South Africa has the most of the first subspecies, The Southern White Rhino (Ceratotherium simum simum). Their population is about 11,000, making them the most abundant subspecies of rhino in the world. Wild-caught southern whites 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, 91 calves have been born at the San Diego Wild Animal Park since 1972. However, for reasons that are not currently understood, the rate of reproduction is extremely low among captive-born southern white females.
There are also two White Rhinos in Livingstone, Zambia (in the Mosi-o-tunia zoological park).
Northern white rhinoceros
The Northern White Rhinoceros (Ceratotherium simum cottoni), formerly found in several countries in East and Central Africa south of the Sahara, is considered Critically Endangered. Their wild population has been reduced from about 500 in the 1970s to only about four today.
Name
The name White Rhino originated in South Africa where the Afrikaans language developed from the Dutch language. The Afrikaans word "wyd" (derived from the Dutch word "wijd"), which means "wide", referred to the width of the Rhinoceros mouth. Early English settlers in South Africa misinterpreted the "wyd" for "white". So the rhino with the wide mouth ended up being called the White Rhino and the other one, with the narrow pointed mouth, was called the Black Rhinoceros. The wide mouth was adapted to cropping large swaths of grass, while the narrow mouth was adapted to eating leaves on bushes. A White Rhino's skin colour is quite similar to that of the Black Rhino. An alternative common name for the white rhinoceros, more accurate but rarely used, is the square-lipped rhinoceros. The White Rhinoceros' genus, Ceratotherium, appropriately means "horned beast". The White Rhinoceros' epithet, simum, is from the Greek simus, meaning "flat nosed" Simum also means a sand storm.
Physical description
The White Rhino has a massive body and large head, a short neck and broad chest. The average size range of a mature rhino is a weight of 1800-3000 kg (4000-6600 lb), a head-and-body length of 3.35-4.2 m (11-13.9 feet) and a shoulder height of 150-185 cm (60-73 inches). The record-sized White Rhinoceros was about 3600 kg. On its snout it has two horns made of keratin fibres as in human fingernails and hair, rather than bone as in deer antlers. The front horn is larger that the other horn and averages 89.9 cm (23.6 inches) in length and can reach 150 cm (59 inches). The White Rhinoceros also has a noticeable hump on the back of its neck which supports its large head. Each of the rhino's four stumpy feet has three toes. The colour of this animal ranges from yellowish brown to slate grey. The only hair on them is on the ear fringes and tail bristles. White Rhinos have the distinctive flat broad mouth which is used for grazing.
Its ears can move independently to pick up more sounds but it depends most of all on smell. The olfactory passages which are responsible for smell are larger than their entire brain.
Behaviour and ecology
They are found in grassland and savannah habitat. Herbivores grazers that eats grass, preferring the shortest grains. The White Rhino is one of the largest pure grazers. Regularly it drinks twice a day if water is available, but if conditions get dry it can live four or five days without water. It spends about half of the day eating, one third resting and the rest of the day doing various other things. White Rhinos like all species of rhino love wallowing in mudholes to cool down.
White rhinos can produce sounds which include a panting contact call, grunts and snorts during courtship, squeals of distress, and deep bellows or growls when threatened. Threat displays (in males mostly) include wiping its horn on the ground and a head-low posture with ears back, combined with snarl threats and shrieking if attacked. Can reach speeds of 18 mph which it can maintain for up to 2 miles, and a galloping speed of 25 mph.
White Rhinos can live in groups of up to 14 animals (usually mostly female). Sub-adult males will congregate, often in association with an adult female. Most adult bulls are solitary. Dominant bulls mark their territory with excrement and urine. The dung is laid in well defined piles. It may have 20-30 of these piles to alert passing rhinos that its his territory. Another way of marking their territory is wiping his horns on bushes or the ground and scrapes with its feet before urine spraying. They do this around 10 times an hour while patrolling territory. The same ritual as urine marking except without spraying is also commonly used. The territorial male will scrape-mark every 30 yards or so around its territory boundary. Subordinate males do not mark territory. The most serious fights break out over mating rights over a female. Female territory is overlapped extensively and they do not defend it.
Reproduction
Females reach sexually maturity 4-5 years while males reach sexual maturity at a later date which is 10-12 years of age. Courtship is often a difficult affair. The male stays beyond the point were the female acts aggressively and will give out a call when approaching her. The male chases and or blocks the way of the female while squealing or loud-wailing if the female tries to leave his territory. When ready to mate the female curls its tail and gets into a stiff stance during the half hour copulation. Breeding pairs stay together between 5-20 days before they part their separate ways. Gestation occurs around 16-18 months. A single calf is born and weighs between 88 and 143 pounds and are unsteady for their first 2 to 3 days of life. When threatened the baby will run in front of the mother. The mother is very protective of her calf and will fight for her baby vigorously. Weaning starts at 2 months and may continue suckling for over 12 months. The birth interval for the White Rhino is between 2 and 3 years. Before giving birth the mother will chase off her current calf. White Rhinos can live up to 40-50 years old.
Population and threats
The northern subspecies is now only found in the Democratic Republic of Congo while the southern subspecies or majority of white rhino live in South Africa. 98.9% of white rhino occur in just four countries (South Africa, Namibia, Zimbabwe and Kenya). Almost decimated to the brink of extinction in early 20th century they have made a tremendous comeback. In 2001 it was estimated that there was 11,670 white rhino in the wild with a further 777 in captivity worldwide making it the most common Rhino in the world.
Like the Black Rhino, the White Rhino is under threat from habitat loss and poaching, most recently by an offshoot of the janjaweed. The horn is mostly used for traditional medicine although there are no health benefits from the horn. Poaching also has occurred for jambiyas which is a dagger used in the Middle East. A recent population count in the Congo turned up only 10 rhinos left in the wild, which led conservationists in January 2005 to propose airlifting White Rhinos from Garamba into Kenya. Although official approval was initially obtained, resentment of foreign interference within the Congo has prevented the airlift from happening as of the beginning of 2006.
http://en.wikipedia.org/wiki/White_Rhinoceros
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