Rock monitor
A white-throated monitor at Kruger National Park, South Africa
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Varanidae
Genus: Varanus
Subgenus: Polydaedalus
Species:
V. albigularis
Binomial name
Varanus albigularis
(Daudin, 1802)[2][3]
Synonyms[4]
  • Tupinambis albigularis
    Daudin, 1802
  • Monitor albigularis
    — Gray, 1831
  • Varanus albogularis
    — A.M.C. Duméril & Bibron, 1836
  • Regenia albogularis
    — Günther, 1861
  • Varanus albigularis
    — Boulenger, 1885
  • Varanus exanthematicus albigularis
    — Schmidt, 1919
  • Varanus albigularis
    — Böhme, 1988

The rock monitor (Varanus albigularis) is a species of monitor lizard in the family Varanidae. The species is endemic to Sub-Saharan Africa. It is on average the largest lizard found on the continent, and is locally called leguaan or likkewaan.

Taxonomy

First described by François Marie Daudin in 1802,[2] V. albigularis has been classified as a subspecies of V. exanthematicus,[5] but has since been declared a distinct species based upon differences in hemipenal morphology.[6] The generic name Varanus is derived from the Arabic word waral ورل, which is translated to English as "monitor". The specific name albigularis comes from a compound of two Latin words: albus meaning "white" and gula meaning "throat".

The subspecies of V. albigularis are:

Description

Varanus albigularis is on average the most massive lizard in Africa, as adult males average about 6 to 8 kg (13 to 18 lb) and females weigh from 3.2 to 5 kg (7.1 to 11.0 lb).[7][8][9] Large mature males can attain weights of 15 to 17 kg (33 to 37 lb), which would make it slightly smaller than the Nile monitor by maximum size.[10] It is the second longest African lizard after the Nile monitor. Mature specimens typically measure 0.85 to 1.5 meters (2 ft 9 in to 4 ft 11 in).[8][10] The head and neck are the same length, and are distinct from each other.[11] The bulbous, convex snout gives an angular, box-like appearance. The forked tongue is pink or bluish,[11] and the body scales are usually a mottled gray-brown with yellowish or white markings.[11] Exceptionally large specimens reach 2 meters (6 ft 7 in) in total length (including tail), with its tail and body being of equal size.[12]

Geographic range and habitat

V. albigularis is found in Central Africa (Democratic Republic of the Congo/Zaire), Southern Africa (Namibia, Botswana, Republic of South Africa, Eswatini, Zimbabwe, Mozambique, Zambia, Angola), the African Great Lakes (Kenya, Uganda, Tanzania), and the Horn of Africa (Ethiopia, Somalia).[11] V. albigularis is found in a variety of dry habitats, including steppes, prairies, and savannahs, but is absent from desert interiors, rainforests, and thick scrub forests.[11]

Diet

V. albigularis are generalists, feeding opportunistically on a broad variety of prey in the wild, such as other lizards, amphibians, birds, snakes, tortoises, eggs and small mammals.[13][14] Tortoises make up a significant part of their diet, and are swallowed whole due to the hard shell. Otherwise, this species consumes very little vertebrate prey, eating primarily invertebrates, especially millipedes, beetles, molluscs, orthopterans and scorpions.[15] Millipedes for example form nearly a quarter of their diet; the monitors are apparently resistant to its poisonous secretions. They are not averse to occasionally scavenging the corpses of vertebrate prey, even those as large as vervet monkeys, which are sometimes torn to pieces by "death rolling" like a crocodilian prior to consumption.[16] Live vertebrate prey other than tortoises are usually too fast to catch for these monitors, and therefore form very little of their diet.[17] This contrasts with what is often a diet of mostly vertebrates in captivity, such as rodents, poultry or fish.[18]

Predator

Natural predators of adult rock monitors include martial eagles and leopard.[19][20]

Intelligence

An intelligent lizard, several specimens of V. albigularis have demonstrated the ability to count as high as six in an experiment conducted by Dr. John Philips at the San Diego Zoo in 1999.[21] Philips offered varying numbers of snails, and the monitors were able to distinguish numbers whenever one was missing.[22][23]

Folklore

People living with the HIV/AIDS virus in Yumbe District of Uganda have been reported injecting themselves with the blood of rock monitors, which they believe to be a cure for the virus.[24] Many are reportedly discontinuing anti-retroviral therapy to pursue this anecdotal treatment.[24]

As a result, V. albigularis is reported to have become an expensive item in the Ugandan black market, selling for more than 175 US$ each.[24]

References

Wikimedia Commons has media related to Varanus albigularis.
Wikispecies has information related to Varanus albigularis.
  1. ↑ Beraduccii, J.; Msuya, C.A.; Howell, K.; Ngalason, W. (2021). "Varanus albigularis". IUCN Red List of Threatened Species. 2021: e.T22473612A22473630. Retrieved 19 November 2021.
  2. 1 2 Daudin FM (1802). Histoire Naturelle, Génerale et Particulière des Reptiles; Ouvrage faisant suite à l'Histoire Naturelle, générale et particulière, composée par LECLERC DE BUFFON, et redigée par C. S. SONNINI, membre de plusieurs Sociétés savantes. Tome Troisième [Volume 3]. Paris: F. Dufart. 452 pp. + Plates I-XLV. (Tupinambis albigularis, new species, pp. 72-75 + Plate XXXII).
  3. ↑ "Varanus albigularis ". Integrated Taxonomic Information System. Retrieved 22 August 2008.
  4. 1 2 "Varanus albigularis ". The Reptile Database. www.reptile-database.org.
  5. ↑ Laurent RF (1964). "A new subspecies of Varanus exanthematicus (Sauria, Varanidae)". Breviora (199): 1-5. (Varanus exanthematicus ionidesii, new subspecies).
  6. ↑ Böhme W (1991). "New finding on the hemipenal morphology of monitor lizards and their systematic implications". Mertensiella 2: 42-49.
  7. ↑ "White Throated Monitor – Varanus albigularis ". Reptiliana: Ultimate Reptile Resource. March 2008. Retrieved 2013-06-06.
  8. 1 2 "African Savannah Monitor – Varanus exanthematicus albigularis ". WAZA : World Association of Zoos and Aquariums. Retrieved 2013-06-06.
  9. ↑ Gardner BR, Barrows MG (2010). "Yolk coelomitis in a white-throated monitor lizard (Varanus albigularis)". Journal of the South African Veterinary Association 81 (2): 121-122.
  10. 1 2 "Varanus albigularis ". Monitor-Lizards.net. Archived from the original on 2012-07-31. Retrieved 2013-06-06.
  11. 1 2 3 4 5 Alexander, Graham; Marais, Johan (2008). A Guide to the Reptiles of Southern Africa. South Africa: Struik Publishers. 408 pp. ISBN 978-1-77007-386-9.
  12. ↑ Carruthers, Vincent (June 5, 2008). The Wildlife of Southern Africa: The Larger Illustrated Guide to the Animals and Plants of the Region. South Africa: Struik Publishers. 320 pp. ISBN 978-1-77007-199-5.
  13. ↑ https://www.researchgate.net/publication/280597661_Varanus_albigularis_-_Diet
  14. ↑ "Varanus Albigularis".
  15. ↑ "Varanus Albigularis".
  16. ↑ Krebs, Uwe (January 2019). "Observations and Experiments on "Spinning Behavior" in Varanus albigularis". Biawak. 13 (1): 54–61.
  17. ↑ Dalhuijsen, Kim (10 December 2013). "A comparative analysis of the diets of Varanusalbigularis and Varanus niloticus in South Africa". African Zoology. 49 (1): 84–93.
  18. ↑ "Black-Throated Monitor 101: Care, Size, Diet & More!". 26 July 2022.
  19. ↑ "Eagle Rips Lizard's Eyes Apart As it Tries to Escape". Kruger sighting. September 15, 2020.
  20. ↑ Radloff, Frans GT, and Johan T. Du Toit. "Large predators and their prey in a southern African savanna: a predator's size determines its prey size range." Journal of Animal Ecology 73.3 (2004): 410-423.
  21. ↑ Pianka, Eric R.; Vitt, Laurie J. (2003). Lizards: Windows to the Evolution of Diversity. Berkeley, Los Angeles, London: University of California Press. 346 pp. ISBN 978-0-520-23401-7.
  22. ↑ King, Dennis; Green, Brian (1999). Goannas: The Biology of Varanid Lizards. University of New South Wales Press. ISBN 0-86840-456-X. p. 43.
  23. ↑ The Weekend Australian. July 24–25, 1999, p. 12.
  24. 1 2 3 "Ugandans turn to varanid lizard blood for AIDS cure" (PDF). BIAWAK. INTERNATIONAL VARANID INTEREST GROUP. 2 (1). February 2008. Retrieved 2008-08-27.

Further reading

  • Bayless, Mark K. (1992). "The Necropsy and internal Anatomy of a white-throated monitor lizard (Varanus albigularis Daudin, 1802)". VaraNews 2 (1): 5-6.
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