Post by Gorilla king on Aug 10, 2021 12:51:37 GMT -5
The white rhinoceros or square-lipped rhinoceros (Ceratotherium simum) is the largest extant species of rhinoceros. It has a wide mouth used for grazing and is the most social of all rhino species. The white rhinoceros consists of two subspecies: the southern white rhinoceros, with an estimated 19,682–21,077 wild-living animals in the year 2015,[3] and the much rarer northern white rhinoceros. The northern subspecies has very few remaining individuals, with only two confirmed left in 2018 (two females; Fatu, 18 and Najin, 29), both in captivity. Sudan, the world's last known male northern white rhinoceros, died in Kenya on 19 March 2018.[4]
Naming
A popular albeit widely discredited theory of the origins of the name "white rhinoceros" is a mistranslation from Dutch to English. The English word "white" is said to have been derived by mistranslation of the Dutch word "wijd", which means "wide" in English. The word "wide" refers to the width of the rhinoceros's mouth. So early English-speaking settlers in South Africa misinterpreted the "wijd" for "white" and 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. Ironically, Dutch (and Afrikaans) later used a calque of the English word, and now also call it a white rhino. This suggests the origin of the word was before codification by Dutch writers. A review of Dutch and Afrikaans literature about the rhinoceros has failed to produce any evidence that the word wijd was ever used to describe the rhino outside of oral use.[5]
An alternative name for the white rhinoceros, more accurate but rarely used, is the square-lipped rhinoceros. The white rhinoceros' generic name, Ceratotherium, given by the zoologist John Edward Gray in 1868,[6] is derived from the Greek terms keras (κέρας) "horn" and thērion (θηρίον) "beast". Simum, is derived from the Greek term simos (σιμός), meaning "flat nosed".
Taxonomy and evolution
The white rhinoceros of today was said to be likely descended from Ceratotherium praecox which lived around 7 million years ago. Remains of this white rhino have been found at Langebaanweg near Cape Town.[7] A review of fossil rhinos in Africa by Denis Geraads has however suggested that the species from Langebaanweg is of the genus Ceratotherium, but not Ceratotherium praecox as the type specimen of Ceratotherium praecox should, in fact, be Diceros praecox, as it shows closer affinities with the black rhinoceros Diceros bicornis.[8] It has been suggested that the modern white rhino has a longer skull than Ceratotherium praecox to facilitate consumption of shorter grasses which resulted from the long-term trend to drier conditions in Africa.[9] However, if Ceratotherium praecox is in fact Diceros praecox, then the shorter skull could indicate a browsing species. Teeth of fossils assigned to Ceratotherium found at Makapansgat in South Africa were analysed for carbon isotopes and the researchers concluded that these animals consumed more than 30% browse in their diet, suggesting that these are not the fossils of the extant Ceratotherium simum which only eats grass.[10] It is suggested that the real lineage of the white rhino should be; Ceratotherium neumayri → Ceratotherium mauritanicum → C. simum with the Langebaanweg rhinos being Ceratotherium sp. (as yet unnamed), with black rhinos being descended from C. neumayri via Diceros praecox.[8]
Recently, an alternative scenario has been proposed[11] under which the earliest African Ceratotherium is considered to be Ceratotherium efficax, known from the Late Pliocene of Ethiopia and the Early Pleistocene of Tanzania. This species is proposed to have been diversified into the Middle Pleistocene species C. mauritanicum in northern Africa, C. germanoafricanum in East Africa, and the extant C. simum. The first two of these are extinct, however, C. germanoafricanum is very similar to C. simum and has often been considered a fossil and ancestral subspecies to the latter. The study also doubts the ancestry of C. neumayri from the Miocene of southern Europe to the African species.[11] It is likely that the ancestor of both the black and the white rhinos was a mixed feeder, with the two lineages then specializing in browsing and grazing, respectively. The oldest definitive record of the White Rhinoceros is during the mid Early Pleistocene at Olduvai Gorge in Tanzania, around 1.8 Ma.[12]
Southern white rhinoceros
Main article: Southern white rhinoceros
There are two subspecies of white rhino: the southern white rhinoceros (Ceratotherium simum simum) and the northern white rhinoceros. As of 31 December 2007, there were an estimated 17,460 southern white rhinos in the wild (IUCN 2008), making them by far the most abundant subspecies of rhino in the world; the number of southern white rhinos outnumbers all other rhino subspecies combined. South Africa is the stronghold for this subspecies (93.0%), conserving 16,255 individuals in the wild in 2007 (IUCN 2008). There are smaller reintroduced populations within the historical range of the species in Namibia, Botswana, Zimbabwe, Uganda and Eswatini, while a small population survives in Mozambique. Populations have also been introduced outside of the former range of the species to Kenya and Zambia.[13]
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. However, for reasons that are not currently understood, the rate of reproduction is extremely low among captive-born southern white females.[14]
Northern white rhinoceros
Main article: Northern white rhinoceros
A northern white rhinoceros crosses the equator during translocation to Ol Pejeta Conservancy
The northern white rhinoceros or northern square-lipped rhinoceros (Ceratotherium simum cottoni) is considered critically endangered and possibly extinct in the wild. Formerly found in several countries in East and Central Africa south of the Sahara, this subspecies is a grazer in grasslands and savanna woodlands.
Initially, six northern white rhinoceros lived in the Dvůr Králové Zoo in the Czech Republic. Four of the six rhinos (which were also the only reproductive animals of this subspecies) were transported to Ol Pejeta Conservancy in Kenya,[15] where scientists hoped they would successfully breed and save this subspecies from extinction. One of two remaining in the Czech Republic died in late May 2011.[16] Both of the last two males capable of natural mating died in 2014 (one in Kenya on 18 October and one in San Diego on 15 December).[17][18] In 2015, the Kenyan government placed the last remaining male of the subspecies at Ol Pejeta under 24-hour armed guard to deter poachers, but he was put down on 19 March 2018 due to multiple health problems caused by old age, leaving just two females alive which reside at the Ol Pejeta complex. Staff hope to inseminate the remaining females with the last male's semen, although the semen is not preferable due to the age of the rhino.[19]
Following the phylogenetic species concept, recent research has led to the hypothesis that the northern white rhinoceros is a different species, rather than a subspecies of white rhinoceros as was previously thought, in which case the correct scientific name for the former should be Ceratotherium cottoni. Distinct morphological and genetic differences suggest the two proposed species have been separated for at least a million years.[20] However, the results of the research were not universally accepted by other scientists.[21]
Description
A diagram showing the size of large white rhino individuals compared to humans.
The white rhinoceros is the largest of the five living species of rhinoceros. By mean body mass, the white rhinoceros falls behind only the three extant species of elephant as the largest land animal and terrestrial mammal alive today.[22][23] It weighs slightly more on average than a hippopotamus despite a considerable mass overlap between these two species.[24] It has a massive body and large head, a short neck and broad chest.
White rhinos have three distinct toes
The head and body length is 3.7 to 4 m (12.1 to 13.1 ft) in males and 3.4 to 3.65 m (11.2 to 12.0 ft) in females,[25] with the tail adding another 70 cm (28 in) and the shoulder height is 170 to 186 cm (5.58 to 6.10 ft) in the male and 160 to 177 cm (5.25 to 5.81 ft) in the female.[25] The male, averaging about 2,300 kg (5,070 lb) is heavier than the female, at an average of about 1,700 kg (3,750 lb).[25] The largest size the species can attain is not definitively known; specimens of up to 3,600 kg (7,940 lb) are considered reliable, while larger sizes up to 4,500 kg (9,920 lb) have been claimed but are not verified.[26][27][28][29] On its snout it has two horn-like growths, one behind the other. These are made of solid keratin, in which they differ from the horns of bovids (cattle and their relatives), which are keratin with a bony core, and deer antlers, which are solid bone.
The skull
Closeup of skin at Lisbon Zoo
The front horn is larger and averages 60 cm (24 in) in length, reaching as much as 150 cm (59 in) but only in females.[30] The white rhinoceros also has a noticeable hump on the back of its neck. Each of the four stumpy feet has three toes. The color of the body ranges from yellowish brown to slate grey. Its only hair is the ear fringes and tail bristles. White rhinos have a distinctive broad, straight mouth which is used for grazing. Its ears can move independently to pick up sounds, but it depends most of all on its sense of smell. The olfactory passages that are responsible for smell are larger than their entire brain. The white rhinoceros has the widest set of nostrils of any land-based animal.
en.m.wikipedia.org/wiki/White_rhinoceros
Naming
A popular albeit widely discredited theory of the origins of the name "white rhinoceros" is a mistranslation from Dutch to English. The English word "white" is said to have been derived by mistranslation of the Dutch word "wijd", which means "wide" in English. The word "wide" refers to the width of the rhinoceros's mouth. So early English-speaking settlers in South Africa misinterpreted the "wijd" for "white" and 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. Ironically, Dutch (and Afrikaans) later used a calque of the English word, and now also call it a white rhino. This suggests the origin of the word was before codification by Dutch writers. A review of Dutch and Afrikaans literature about the rhinoceros has failed to produce any evidence that the word wijd was ever used to describe the rhino outside of oral use.[5]
An alternative name for the white rhinoceros, more accurate but rarely used, is the square-lipped rhinoceros. The white rhinoceros' generic name, Ceratotherium, given by the zoologist John Edward Gray in 1868,[6] is derived from the Greek terms keras (κέρας) "horn" and thērion (θηρίον) "beast". Simum, is derived from the Greek term simos (σιμός), meaning "flat nosed".
Taxonomy and evolution
The white rhinoceros of today was said to be likely descended from Ceratotherium praecox which lived around 7 million years ago. Remains of this white rhino have been found at Langebaanweg near Cape Town.[7] A review of fossil rhinos in Africa by Denis Geraads has however suggested that the species from Langebaanweg is of the genus Ceratotherium, but not Ceratotherium praecox as the type specimen of Ceratotherium praecox should, in fact, be Diceros praecox, as it shows closer affinities with the black rhinoceros Diceros bicornis.[8] It has been suggested that the modern white rhino has a longer skull than Ceratotherium praecox to facilitate consumption of shorter grasses which resulted from the long-term trend to drier conditions in Africa.[9] However, if Ceratotherium praecox is in fact Diceros praecox, then the shorter skull could indicate a browsing species. Teeth of fossils assigned to Ceratotherium found at Makapansgat in South Africa were analysed for carbon isotopes and the researchers concluded that these animals consumed more than 30% browse in their diet, suggesting that these are not the fossils of the extant Ceratotherium simum which only eats grass.[10] It is suggested that the real lineage of the white rhino should be; Ceratotherium neumayri → Ceratotherium mauritanicum → C. simum with the Langebaanweg rhinos being Ceratotherium sp. (as yet unnamed), with black rhinos being descended from C. neumayri via Diceros praecox.[8]
Recently, an alternative scenario has been proposed[11] under which the earliest African Ceratotherium is considered to be Ceratotherium efficax, known from the Late Pliocene of Ethiopia and the Early Pleistocene of Tanzania. This species is proposed to have been diversified into the Middle Pleistocene species C. mauritanicum in northern Africa, C. germanoafricanum in East Africa, and the extant C. simum. The first two of these are extinct, however, C. germanoafricanum is very similar to C. simum and has often been considered a fossil and ancestral subspecies to the latter. The study also doubts the ancestry of C. neumayri from the Miocene of southern Europe to the African species.[11] It is likely that the ancestor of both the black and the white rhinos was a mixed feeder, with the two lineages then specializing in browsing and grazing, respectively. The oldest definitive record of the White Rhinoceros is during the mid Early Pleistocene at Olduvai Gorge in Tanzania, around 1.8 Ma.[12]
Southern white rhinoceros
Main article: Southern white rhinoceros
There are two subspecies of white rhino: the southern white rhinoceros (Ceratotherium simum simum) and the northern white rhinoceros. As of 31 December 2007, there were an estimated 17,460 southern white rhinos in the wild (IUCN 2008), making them by far the most abundant subspecies of rhino in the world; the number of southern white rhinos outnumbers all other rhino subspecies combined. South Africa is the stronghold for this subspecies (93.0%), conserving 16,255 individuals in the wild in 2007 (IUCN 2008). There are smaller reintroduced populations within the historical range of the species in Namibia, Botswana, Zimbabwe, Uganda and Eswatini, while a small population survives in Mozambique. Populations have also been introduced outside of the former range of the species to Kenya and Zambia.[13]
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. However, for reasons that are not currently understood, the rate of reproduction is extremely low among captive-born southern white females.[14]
Northern white rhinoceros
Main article: Northern white rhinoceros
A northern white rhinoceros crosses the equator during translocation to Ol Pejeta Conservancy
The northern white rhinoceros or northern square-lipped rhinoceros (Ceratotherium simum cottoni) is considered critically endangered and possibly extinct in the wild. Formerly found in several countries in East and Central Africa south of the Sahara, this subspecies is a grazer in grasslands and savanna woodlands.
Initially, six northern white rhinoceros lived in the Dvůr Králové Zoo in the Czech Republic. Four of the six rhinos (which were also the only reproductive animals of this subspecies) were transported to Ol Pejeta Conservancy in Kenya,[15] where scientists hoped they would successfully breed and save this subspecies from extinction. One of two remaining in the Czech Republic died in late May 2011.[16] Both of the last two males capable of natural mating died in 2014 (one in Kenya on 18 October and one in San Diego on 15 December).[17][18] In 2015, the Kenyan government placed the last remaining male of the subspecies at Ol Pejeta under 24-hour armed guard to deter poachers, but he was put down on 19 March 2018 due to multiple health problems caused by old age, leaving just two females alive which reside at the Ol Pejeta complex. Staff hope to inseminate the remaining females with the last male's semen, although the semen is not preferable due to the age of the rhino.[19]
Following the phylogenetic species concept, recent research has led to the hypothesis that the northern white rhinoceros is a different species, rather than a subspecies of white rhinoceros as was previously thought, in which case the correct scientific name for the former should be Ceratotherium cottoni. Distinct morphological and genetic differences suggest the two proposed species have been separated for at least a million years.[20] However, the results of the research were not universally accepted by other scientists.[21]
Description
A diagram showing the size of large white rhino individuals compared to humans.
The white rhinoceros is the largest of the five living species of rhinoceros. By mean body mass, the white rhinoceros falls behind only the three extant species of elephant as the largest land animal and terrestrial mammal alive today.[22][23] It weighs slightly more on average than a hippopotamus despite a considerable mass overlap between these two species.[24] It has a massive body and large head, a short neck and broad chest.
White rhinos have three distinct toes
The head and body length is 3.7 to 4 m (12.1 to 13.1 ft) in males and 3.4 to 3.65 m (11.2 to 12.0 ft) in females,[25] with the tail adding another 70 cm (28 in) and the shoulder height is 170 to 186 cm (5.58 to 6.10 ft) in the male and 160 to 177 cm (5.25 to 5.81 ft) in the female.[25] The male, averaging about 2,300 kg (5,070 lb) is heavier than the female, at an average of about 1,700 kg (3,750 lb).[25] The largest size the species can attain is not definitively known; specimens of up to 3,600 kg (7,940 lb) are considered reliable, while larger sizes up to 4,500 kg (9,920 lb) have been claimed but are not verified.[26][27][28][29] On its snout it has two horn-like growths, one behind the other. These are made of solid keratin, in which they differ from the horns of bovids (cattle and their relatives), which are keratin with a bony core, and deer antlers, which are solid bone.
The skull
Closeup of skin at Lisbon Zoo
The front horn is larger and averages 60 cm (24 in) in length, reaching as much as 150 cm (59 in) but only in females.[30] The white rhinoceros also has a noticeable hump on the back of its neck. Each of the four stumpy feet has three toes. The color of the body ranges from yellowish brown to slate grey. Its only hair is the ear fringes and tail bristles. White rhinos have a distinctive broad, straight mouth which is used for grazing. Its ears can move independently to pick up sounds, but it depends most of all on its sense of smell. The olfactory passages that are responsible for smell are larger than their entire brain. The white rhinoceros has the widest set of nostrils of any land-based animal.
en.m.wikipedia.org/wiki/White_rhinoceros
