The rock monitor (Varanus albigularis) is a species of monitor lizard in the family Varanidae. The species is endemic to Central, East, and southern Africa. It is the second-longest lizard found on the continent, and the heaviest-bodied; locally, it is called leguaan or likkewaan.
First described by François Marie Daudin in 1802, V. albigularis has been classified as a subspecies of V. exanthematicus, but has since been declared a distinct species based upon differences in hemipenal morphology. 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:
- White-throated monitor, V. a. albigularis
- Angolan white-throated monitor, V. a. angolensis
- Eastern white-throated monitor, V. a. microstictus
- Black-throated monitor, V. a. ionidesi  (but may be synonymous with V. a. microstictus)
Varanus albigularis is the heaviest-bodied 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). Large mature males can attain 15 to 17 kg (33 to 37 lb). It is the second longest African lizard after the Nile monitor (Varanus niloticus). Varanus albigularis reaches 2 meters (6 ft 7 in) in total length (including tail), with its tail and body being of equal size. Mature specimens more typically will measure 0.85 to 1.5 meters (2 ft 9 in to 4 ft 11 in). The head and neck are the same length, and are distinct from each other. The bulbous, convex snout gives an angular, box-like appearance. The forked tongue is pink or bluish, and the body scales are usually a mottled gray-brown with yellowish or white markings.
V. albigularis are generalists, feeding opportunistically on a broad variety of prey in the wild. 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 and orthopterans. 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. Live vertebrate prey other than tortoises are usually too fast to catch for these monitors, and therefore form very little of their diet. This contrasts with what is often a diet of mostly vertebrates in captivity, such as rodents or poultry.
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. Philips offered varying numbers of snails, and the monitors were able to distinguish numbers whenever one was missing.
V. albigularis is found in Central Africa (Democratic Republic of the Congo/Zaire), Southern Africa (Namibia, Botswana, Republic of South Africa, Swaziland, Zimbabwe, Mozambique, Zambia, Angola), the African Great Lakes (Kenya, Uganda, Tanzania), and the Horn of Africa (Ethiopia, Somalia).
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. Many are reportedly discontinuing anti-retroviral therapy to pursue this anecdotal treatment.
|Wikimedia Commons has media related to Varanus albigularis.|
|Wikispecies has information related to Varanus albigularis|
- 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).
- "Varanus albigularis ". Integrated Taxonomic Information System. Retrieved 22 August 2008.
- "Varanus albigularis ". The Reptile Database. www.reptile-database.org. 
- Laurent RF (1964). "A new subspecies of Varanus exanthematicus (Sauria, Varanidae)". Breviora (199): 1-5. (Varanus exanthematicus ionidesii, new subspecies).
- Böhme W (1991). "New finding on the hemipenal morphology of monitor lizards and their systematic implications". Mertensiella 2: 42-49.
- "White Throated Monitor – Varanus albigularis ". Reptiliana: Ultimate Reptile Resource. March 2008. Retrieved 2013-06-06.
- "African Savannah Monitor – Varanus exanthematicus albigularis ". WAZA : World Association of Zoos and Aquariums. Retrieved 2013-06-06.
- 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.
- "Varanus albigularis ". Monitor-Lizards.net. Archived from the original on 2012-07-31. Retrieved 2013-06-06.
- 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.
- 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.
- Krebs, Uwe (January 2019). "Observations and Experiments on "Spinning Behavior" in Varanus albigularis". Biawak. 13 (1): 54–61.
- 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.
- 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.
- King, Dennis; Green, Brian (1999). Goannas: The Biology of Varanid Lizards. University of New South Wales Press. ISBN 0-86840-456-X. p. 43.
- The Weekend Australian. July 24–25, 1999, p. 12.
- "Ugandans turn to varanid lizard blood for AIDS cure" (PDF). BIAWAK. INTERNATIONAL VARANID INTEREST GROUP. 2 (1). February 2008. Retrieved 2008-08-27.
- Bayless, Mark K. (1992). "The Necropsy and internal Anatomy of a white-throated monitor lizard (Varanus albigularis Daudin, 1802)". VaraNews 2 (1): 5-6.