Northern white rhinoceros: Difference between revisions
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== Living rhinos == |
== Living rhinos == |
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== Recently deceased rhinos == |
== Recently deceased rhinos == |
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=== Wild Population === |
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The northern white rhino (''Ceratotherium simum cottoni'') formerly ranged over parts of northwestern [[Uganda]], southern [[South Sudan]], the eastern part of [[Central African Republic]], and northeastern [[Democratic Republic of the Congo]].<ref name=sydney>{{cite journal | author = Sydney, J. |year=1965|title= The past and present distribution of some African ungulates|journal= Transactions of the Zoological Society of London |volume=3|pages=1–397|doi=10.1017/S0030605300006815 }}</ref> Their range possibly extended as far west as [[Lake Chad]], into [[Chad]] and [[Cameroon]].{{citation needed|date=August 2014}} |
The northern white rhino (''Ceratotherium simum cottoni'') formerly ranged over parts of northwestern [[Uganda]], southern [[South Sudan]], the eastern part of [[Central African Republic]], and northeastern [[Democratic Republic of the Congo]].<ref name=sydney>{{cite journal | author = Sydney, J. |year=1965|title= The past and present distribution of some African ungulates|journal= Transactions of the Zoological Society of London |volume=3|pages=1–397|doi=10.1017/S0030605300006815 }}</ref> Their range possibly extended as far west as [[Lake Chad]], into [[Chad]] and [[Cameroon]].{{citation needed|date=August 2014}} |
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Revision as of 12:59, 26 November 2018
Northern white rhinoceros | |
---|---|
Angalifu, a male northern white rhinoceros at the San Diego Zoo Safari Park. Angalifu died from old age 14 December 2014.[1] | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Perissodactyla |
Family: | Rhinocerotidae |
Genus: | Ceratotherium |
Species: | |
Subspecies: | C. s. cottoni
|
Trinomial name | |
Ceratotherium simum cottoni (Lydekker, 1908)
| |
Orange = Northern white rhino range, Green = Southern white rhino range |
The northern white rhinoceros, or northern square-lipped rhinoceros (Ceratotherium simum cottoni), is one of two subspecies of the white rhinoceros (the other being the southern white rhinoceros). Formerly found in several countries in East and Central Africa south of the Sahara, this subspecies is a grazer in grasslands and savanna woodlands. As of 19 March 2018 there were only two known rhinos of this subspecies left, both of which are female; barring the existence of unknown or misclassified male northern white rhinos elsewhere in Africa, this makes the subspecies functionally extinct. The two female rhinos belong to the Dvůr Králové Zoo in the Czech Republic but live in the Ol Pejeta Conservancy in Kenya and are protected round-the-clock by armed guards.
According to the latest International Union for Conservation of Nature (IUCN) assessment from 2011, the subspecies is considered "Critically Endangered (Possibly Extinct in the Wild)."[2]
Living rhinos
Recently deceased rhinos
Wild Population
The northern white rhino (Ceratotherium simum cottoni) formerly ranged over parts of northwestern Uganda, southern South Sudan, the eastern part of Central African Republic, and northeastern Democratic Republic of the Congo.[3] Their range possibly extended as far west as Lake Chad, into Chad and Cameroon.[citation needed]
Poachers reduced their population from 500 to 15 in the 1970s and 1980s. From the early 1990s through mid-2003, the population recovered to more than 32 animals.[4][5] Since mid-2003, poaching has intensified and further reduced the wild population.[4]
Garamba National Park
The last known surviving population of wild northern white rhinos was in Garamba National Park, Democratic Republic of the Congo (DRC).[6]
In January 2005, the government of the DRC approved a two-part plan for five northern white rhinos to be moved from Garamba National Park to a wildlife sanctuary in Kenya. The second part commits the government and its international partners to increase conservation efforts in Garamba, so the northern white rhinos can be returned when it is safe again.[7] However, the translocation did not occur.
In August 2005, ground and aerial surveys conducted under the direction of African Parks Foundation and the African Rhino Specialist Group (ARSG) had only found four animals, a solitary adult male and a group of one adult male and two adult females.[8] They were the last known wild northern white rhinos, according to the World Wide Fund for Nature.[9]
In June 2008, it was reported that the species may have gone extinct in the wild, since there has been no sighting of these four known remaining individuals since 2006, or of their signs since 2007, despite intensive systematic ground and aerial searches in 2008.[2][10] One carcass has been found.[2][11][12] On 28 November 2009, two Russian helicopter pilots reported seeing rhinoceroses in southern Sudan.[13] It was assumed that the three rhinos that were spotted belonged to the northern white rhinoceros subspecies, as black rhinos had not lived in the area for a long time and southern white rhinos never lived in southern Sudan.[14] However, as of August 2011, no other sightings have been reported, and this population is now considered to have probably gone extinct.[2]
Captive population
At the beginning of 2015, the fully captive northern white rhino population consisted of only two animals maintained in two zoological institutions: in the United States (San Diego Zoo Safari Park) and the Czech Republic (Dvůr Králové Zoo). However, both of them died later the same year, and no zoo in the world has any northern white rhinos any longer.
Dvůr Králové Zoo
In 1975, the Dvůr Králové Zoo, located in Dvůr Králové nad Labem, Czech Republic, got six northern white rhinos from Sudan and, in later years, two more from English zoos. One rhino from an English zoo arrived pregnant. The Dvůr Králové Zoo is the only one in the world where northern white rhinos birthed offspring, with the last calf being born in 2000;[15] the current world population consists of their shared descendants.[16][17][18]
Former residents include:
- Ben, a male wild born in Africa in about 1951. He was transferred to Dvůr Králové Zoo from a faculty in England and died 25 June 1990.[17]
- Nasima, a female wild born in Uganda in about 1965. She was transferred pregnant to Dvůr Králové Zoo from a faculty in England. She was the mother of Nasi, Suni, Nabire, and Najin. She birthed four out of five Northern White Rhino calves born in captivity, making her the most fruitful Northern White in captivity to date.[17][19] She died in 1992 at about age 27.[18]
- Saut, a male caught from the wild in Sudan in 1975 at about 3 years of age.[17] He was the father of Suni and Fatu. He was loaned to San Diego Zoo Safari Park by Dvůr Králové Zoo from 1989 until 1998 when he was returned to Dvůr Králové Zoo. He mated with females at both faculties.[18][20] He died in August 2006 around age 33.[21]
- Nuri, a female caught from the wild in Sudan in 1975 at about 3 years of age. She died 4 January 1982 at about age 10.[17]
- Nesari, a female caught from the wild in Sudan in 1975 at about 3 years of age. She died in 2011 at age 39.[22][17]
- Nasi, a female born at Dvůr Králové Zoo on 11 November 1977 and died in 2007. Her mother was Nasima and her father was a southern white rhino, which made her a northern and southern white rhino hybrid.[17][23]
- Suni, a male born at Dvůr Králové Zoo on 8 June 1980. He was the half-brother of Najin and Fatu, but through different parents. His mother was Nasima and his father was Saut.[18][17] He had mated while in zoos. Was transferred to Ol Pejeta Conservancy in 2009. Some of his sperm has been collected and frozen. On 17 October 2014, he died from natural causes, probably old age.[24][25]
- Nabire, born at Dvůr Králové Zoo on 15 November 1983. Her mother was Nasima and her father was Sudan. She died on 27 July 2015.[17][26]
- Sudan, caught from the wild in Sudan in 1975 at about 3 years of age. He was the father of Najin and the late Nabire.[17][19] In March 2018, his state seriously deteriorated despite intensive care due to a recurrent infection in his right hind leg,[27] and he was euthanized on 19 March 2018.[28][29] He was the last known male of the subspecies.
Dvůr Králové Zoo sent Suni, Sudan and two females, which are still alive, to the Ol Pejeta Conservancy in Kenya on 19 December 2009[30] in a joint effort by the zoo, Fauna and Flora International, Back to Africa, Lewa, and Kenya Wildlife Service. Hoping to stimulate the rhinos' sexual appetite, the zoo decided to send them back into their natural habitat in Kenya. The agreement with the Kenyan government expects the rhinos never to be returned to the Czech Republic.
The female named Nabire stayed in Dvůr Králové Zoo, because, as Jan Stejskal, a projects coordinator at the zoo, stated, "she is no longer capable of breeding naturally. But it seems she has one healthy ovary and this could provide us with material from which to create an embryo in artificial conditions."[15] Efforts to do so began in autumn 2014.[31] Immediately after the death of Nabire in 2015, her ovary with four oocytes was removed and transferred to a laboratory in Cremona, Italy. The laboratory was able to extract two egg cells and fertilise them. However, without consulting the Dvůr Králové Zoo, the semen of a southern white rhino was used instead of a northern white rhino, which the zoo considers a wasted opportunity.[32] Neverthelees, the experiment showed that vible hybrid embryos of the northern and southern white rhino are possible through IVF, as well as a path to the creation of pure northern white rhino embryos.[33][34]
San Diego Zoo Safari Park
The San Diego Zoo Safari Park in San Diego, California, had eight wild-caught northern white rhinos.[35][18]
Former residents include:
- Dinka, a male caught from the wild in Sudan in 1957 at about 5 years of age, which arrived from another U.S. zoo in 1972. He died in 1974.[18]
- Bill, a male caught from the wild in Sudan in 1956 at about 4 years of age, which arrived from another U.S. zoo in 1972. He died in 1975.[18]
- Lucy, a male caught from the wild in Sudan in 1956 at about 4 years of age, which arrived from another U.S. zoo in 1972. He died in 1979.[18]
- Joyce, a female caught from the wild in Sudan in 1957 at about 5 years of age, which arrived from another U.S. zoo in 1972. She died in 1996.[18]
- Saut, a male caught from the wild in Sudan in 1975 at about 3 years of age, which was on loan from Dvůr Králové Zoo from 1989–1998. He died in August 2006 at about age 33.[18][21]
- Nadi, a female caught from the wild in Sudan in 1975 at about 3 years of age, which was on loan since 1989 from Dvůr Králové Zoo. She died on 30 May 2007 at about age 35.[35][18]
- Angalifu, a male caught from the wild in Sudan in 1973 at about 1 year of age, which was on loan since 1990 from Khartoum Zoo in Khartoum. He died on 14 December 2014 at about age 42.[1][18]
- Nola, a female caught from the wild in Sudan in 1975 at about 1 year of age, which was on loan since 1989 from Dvůr Králové Zoo.[36][37][38] She died on 22 November 2015 at about age 41.[39]
The San Diego Wild Animal Park provided Angalifu's semen to female rhinos at the Dvůr Králové Zoo but the insemination attempts were unsuccessful. The only reproductive animals of this subspecies were transported to Ol Pejeta Conservancy in Kenya.
In 2016, it was reported that scientists were exploring alternatives (such as artificial insemination, in vitro fertilization and embryo transfer) to develop northern white rhino embryos and implant them in female southern white rhinos at the San Diego Zoo.[40]
List
Stud # | Sex | Name | Date of birth | Place of birth | Date of death | Place of death |
---|---|---|---|---|---|---|
15 | M | Paul | 1948-08-07 | Sudan | 1968-04-13 | Antwerp Zoo |
16 | F | Chloe | 1948-06-07 | Sudan | 1985-08-07 | Antwerp Zoo |
19 | M | Ben | 1950-07-25 | Uganda | 1990-06-25 | Dvůr Králové Zoo |
27 | M | Bill | 1954-03-04 | Sudan | 1975-05-02 | San Diego Zoo Safari Park |
28 | F | Lucy | 1954-03-04 | Sudan | 1979-03-15 | San Diego Zoo Safari Park |
54 | M | [n/a] | 1963-04-01 | Sudan | 1985-12-31 | Riyadh National Zoo |
55 | F | [n/a] | 1963-04-01 | Sudan | 1985-12-31 | Riyadh National Zoo |
74 | M | Dinka | 1952-07-28 | South Sudan | 1991-01-28 | San Diego Zoo Safari Park |
75 | F | Joyce | 1953-01-28 | South Sudan | 1974-08-15 | San Diego Zoo Safari Park |
290 | F | Bebe | 1950-07-01 | Uganda | 1964-05-29 | Zoological Society of London |
345 | F | Tofacha | 1970-01-01 | Sudan | 1978-09-12 | Al Ain Zoo |
347 | M | [n/a] | 1968-04-01 | Sudan | 1978-01-18 | Khartoum Zoo |
348 | M | Angalifu | 1972-04-01 | Sudan | 2014-12-14 | San Diego Zoo Safari Park |
351 | F | Nasima | 1965-07-01 | Uganda | 1992-08-28 | Dvůr Králové Zoo |
372 | M | Sudan | 1973-09-19 | Sudan | 2018-03-19 | Ol Pejeta Conservancy |
373 | M | Saut | 1972-09-19 | Sudan | 2006-08-14 | Dvůr Králové Zoo |
374 | F | Nola | 1974-09-19 | Sudan | 2015-11-22 | San Diego Zoo Safari Park |
375 | F | Nuri | 1973-09-19 | Sudan | 1982-01-04 | Dvůr Králové Zoo |
376 | F | Nadi | 1972-09-19 | Sudan | 2007-05-30 | San Diego Zoo Safari Park |
377 | F | Nesari | 1972-09-19 | Sudan | 2011-05-26 | Dvůr Králové Zoo |
476 | F | Nasi | 1977-11-11 | Dvůr Králové Zoo | 2007-07-20 | Dvůr Králové Zoo |
630 | M | Suni | 1980-06-08 | Dvůr Králové Zoo | 2014-10-18 | Ol Pejeta Conservancy |
789 | F | Nabire | 1983-11-15 | Dvůr Králové Zoo | 2015-07-27 | Dvůr Králové Zoo |
943 | F | Najin | 1989-07-11 | Dvůr Králové Zoo | ||
1122 | F | [n/a] | 1991-07-18 | Dvůr Králové Zoo | 1991-07-18 | Dvůr Králové Zoo |
1123 | F | [n/a] | 1963-04-01 | Sudan | 1967-08-02 | Khartoum Zoo |
1252 | ? | [n/a] | 1948-11-17 | Sudan | 1949-01-29 | Khartoum Zoo |
1305 | F | Fatu | 2000-06-29 | Dvůr Králové Zoo |
Population chart
Location | 1909[43] | 1960* | 1975* | 1984 | 1995 | 1996 | 1998 | 2000 | 2003 | 2006 | 2007 | 2008 | 2009 | 2011 | 2014 | 2015 | 2017 | 2018 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Wild | 2,000–3,000* | 2,000*[44] | 500*[4] | 15[19] | 35[19] | 29[5] | 26-31[5] | 30-36[5] | 30[11] | 4[11] | n/a | 0[11][19] | 0 | 0 | 0 | 0 | 0 | 0 |
Central African Republic | n/a | n/a | n/a | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Dem. Republic of Congo | n/a | n/a | n/a | 15 | 35 | 29 | 26-31 | 30-36 | 30 | 4 | n/a | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
South Sudan | n/a | n/a | n/a | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Uganda | n/a | n/a | n/a | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Captivity | n/a | 7[18] | 15[18] | 16[17][18] | 11[17][18] | 10[17][18] | 10[17][18] | 11[17][18] | 11[17][18] | 10[17][18][21] | 8[18][23][35] | 8[45] | 8[45] | 7[46] | 5[1] | 3[39] | 3[47] | 2[48] |
Dvůr Králové Zoo,
Czech Republic |
n/a | 0 | 6 | 9 | 6 | 6 | 7 | 8 | 8 | 7 | 6 | 6 | 2 | 1 | 1 | 0 | 0 | 0 |
Khartoum Zoo, Sudan | n/a | 0 | 2 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Ol Pejeta
Conservancy, Kenya |
n/a | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 4 | 4 | 3 | 3 | 3 | 2 |
San Diego Zoo, USA | n/a | 0 | 2 | 1 | 5 | 4 | 3 | 3 | 3 | 3 | 2 | 2 | 2 | 2 | 1 | 0 | 0 | 0 |
Other zoo faculties | n/a | 7 | 5 | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Total | 2,000-
3,000* |
2,000* | 500* | 31 | 46 | 39 | 36-41 | 41-47 | 41 | 14 | 8 | 8 | 8 | 7 | 5 | 3 | 3 | 2 |
*estimate
Taxonomy
Following the phylogenetic species concept, recent research has suggested the northern white rhinoceros may be an altogether different species, rather than a subspecies of white rhinoceros, in which case the correct scientific name for the former is Ceratotherium cottoni. Distinct morphological and genetic differences suggest the two proposed species have been separated for at least a million years.[49] However, the results of the research were not universally accepted by other scientists.[2]
References
- ^ a b c "A northern white rhino has died. There are now five left in the entire world". The Washington Post. 15 December 2014.
- ^ a b c d e f "The IUCN Red List of Threatened Species". IUCN Red List of Threatened Species. Retrieved 15 November 2018.
- ^ Sydney, J. (1965). "The past and present distribution of some African ungulates". Transactions of the Zoological Society of London. 3: 1–397. doi:10.1017/S0030605300006815.
- ^ a b c International Rhino Foundation. 2002. Rhino Information – Northern White Rhino. 19 September 2006
- ^ a b c d Smith, Kes Hillman (July–December 2001). "Status of northern white rhinos and elephants in Garamba National Park, Democratic Republic of the Congo, during the wars" (PDF). Pachyderm journal of the African Elephant, African Rhino and Asian Rhino Specialist Groups. 31: 79–81.
- ^ "white rhino - Mammals of Papua". 7 December 2014. Archived from the original on 7 December 2014.
{{cite web}}
: Unknown parameter|deadurl=
ignored (|url-status=
suggested) (help) - ^ IUCN. (25 January 2005). Reprieve planned for Garamba's rhinos: extra efforts promised to safeguard their homeland. Gland, Switzerland.
- ^ IUCN. (6 July 2006). West African black rhino feared extinct. Gland, Switzerland.
- ^ "Northern White Rhino". Worldwildlife.org. Archived from the original on 5 June 2011. Retrieved 7 April 2009.
- ^ Smith, Lewis (17 June 2008). "News | Poachers kill last four wild northern white rhinos". The Times. London. Archived from the original on 29 June 2011. Retrieved 7 April 2009.
- ^ a b c d Smith, Lewis (17 June 2008) Poachers kill last four wild northern white rhinos. The Times.
- ^ Skinner, J.D. and Smithers, R.H.N. (1990). The Mammals of the Southern African Subregion, Cambridge University Press, p. 567, ISBN 0521844185.
- ^ An alternative approach to species conservation. Back to Africa (20 December 2009). Retrieved 7 April 2013.
- ^ V Súdánu objevili téměř vyhynulé bílé nosorožce. Novinky.cz (3 January 2010). Retrieved 7 April 2013.
- ^ a b Lazarová, Daniela (25 September 2014). "Dvůr Králové Zoo spearheading international efforts to save northern white rhino from extinction". Radio Prague. Archived from the original on 26 September 2014.
{{cite web}}
: Unknown parameter|deadurl=
ignored (|url-status=
suggested) (help) - ^ Královédvorská zoo spouští unikátní projekt na záchranu vzácných nosorožců –. Novinky.cz. Retrieved 16 April 2015.
- ^ a b c d e f g h i j k l m n o p q Cite error: The named reference
Breeding Experience With Northern White Rhinos At Zoo Dvur Kralove
was invoked but never defined (see the help page). - ^ a b c d e f g h i j k l m n o p q r s t u v Cite error: The named reference
Captive-rhino-history-as-of-2000
was invoked but never defined (see the help page). - ^ a b c d e Northern white rhinos. Public Broadcasting Service (28 July 2016) Retrieved 31 August 2017.
- ^ Breeding rhinos: Not an easy chore. CNN(2 March 1996) Retrieved 31 August 2017.
- ^ a b c The Rhino Resource Center – Rhino Images. Rhinoresourcecenter.com. Retrieved 7 April 2013.
- ^ Johnston, Raymond (2 June 2011). "White rhino dies in Czech zoo, seven left worldwide". Czech Position. Archived from the original on 13 April 2014.
- ^ a b The Sixth Rhino: A Taxonomic Re-Assessment of the Critically Endangered Northern White Rhinoceros. journals.plos.org. Retrieved 31 August 2017.
- ^ Cite error: The named reference
thedodo.com
was invoked but never defined (see the help page). - ^ Cite error: The named reference
novinky.cz
was invoked but never defined (see the help page). - ^ Rare rhino dies at Czech zoo, leaving just four northern white rhino on Earth. The Guardian (28 July 2015) Retrieved 31 August 2017.
- ^ Torchia, Christopher (1 March 2018). "Health of world's last male northern white rhino in decline". ABC News.
- ^ Cite error: The named reference
ReutersSudan
was invoked but never defined (see the help page). - ^ Cite error: The named reference
putdown
was invoked but never defined (see the help page). - ^ Four of the World's Last Known Eight Northern White Rhinos Come Home to Africa Archived 30 March 2010 at the Wayback Machine, Ol Pejeta website, Saturday, 19 December 2009
- ^ "Zoo se snaží rozmnožit nosorožce, samici Nabiré zavěsili na jeřáb". Mladá fronta DNES (in Czech). 8 October 2014. Retrieved 19 October 2014.
- ^ Tůmová, Štěpánka (4 August 2015) V Itálii oplodnili vajíčka uhynulé nosorožčí samice, ale špatným semenem – iDNES.cz. Hradec.idnes.cz. Retrieved on 24 November 2015.
- ^ https://www.economist.com/science-and-technology/2018/07/05/ivf-may-bring-northern-white-rhinos-back-from-the-brink-of-extinction
- ^ https://www.novinky.cz/veda-skoly/488517-pro-zachranu-nosorozcu-maji-vedci-dostatek-genetickych-zdroju.html
- ^ a b c Eastman, Q. (2007) Northern white rhinos in danger. North County Times (11 June 2007) via Web Archive.
- ^ Last Chance to Survive: Northern White Rhino Conservation Project. Frequently Asked Questions. Northern white rhino. olpejetaconservancy.org
- ^ Severní bílí nosorožci v zajetí. .rozhlas.cz. Retrieved on 24 November 2015.
- ^ Kohoutová, Kateřina (13 May 2015) Samice nosorožce bílého Nola je nemocná. Patří k posledním zvířatům svého druhu | Příroda. Rozhlas.cz. Retrieved on 24 November 2015.
- ^ a b "Nola, a northern white rhino at San Diego Zoo's Safari Park, has died". latimes.com. Retrieved 22 November 2015.
- ^ Morrow, Chris (5 February 2016). "Bringing Northern White Rhinos Back From Brink of Extinction". Huffington Post. Retrieved 24 February 2016.
- ^ Dr Andreas Ochs. "International studbook for the African white rhinoceros, Ceratotherium simum (Burchell, 1817), 01.01.2001 Ninth edition". Rhino Resource Center. Retrieved 31 March 2018.
- ^ Joe Christman. "International studbook for the white rhinoceros Ceratotherium simum (Burchell 1817), vol. 12 (status 31.12.2011)". Rhino Resource Center. p. 289-291. Retrieved 31 March 2018.
- ^ "The White Rhinoceros". diglib1.amnh.org. Retrieved 2 September 2015.
- ^ Cite error: The named reference
:2
was invoked but never defined (see the help page). - ^ a b Final hope: four white rhinos shipped to Kenya. theguardian.org. (20 December 2009) Retrieved 11 September 2017.
- ^ Johnston, Raymond. "White rhino dies in Czech zoo, seven left worldwide". Czech Position. Archived from the original on 13 April 2014. Retrieved 11 September 2017.
- ^ "With 1 male left worldwide, northern white rhinos under guard 24 hours". cnn.com. Retrieved 11 September 2017.
- ^ "Sudan, the last male northern white rhino has passed". reuters.com. Retrieved 20 March 2018.
- ^ Groves, C.P.; Fernando, P.; Robovský, J. (2010). "The sixth rhino: A taxonomic re-assessment of the critically endangered northern white rhinoceros". PLoS ONE. 5 (4): e9703. Bibcode:2010PLoSO...5.9703G. doi:10.1371/journal.pone.0009703. PMC 2850923. PMID 20383328.
{{cite journal}}
: CS1 maint: unflagged free DOI (link)
Further reading
- Rookmaker, L.C. (1998). The Rhinoceros in Captivity. The Hague: SPB Academic Publishing. p. 409. ISBN 90-5103-134-3. Retrieved 22 March 2018.