Nile monitor

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Nile monitor
Nile Monitor, Lake Manyara.jpg
Lake Manyara, Tanzania
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Lacertilia
Family: Varanidae
Genus: Varanus
Subgenus: Polydaedalus
Species: V. niloticus
Binomial name
Varanus niloticus
(Linnaeus, 1758)
  • Lacerta monitor Linnaeus 1758
  • Lacertus tupinambis Lacépède 1788
  • Lacerta capensis Sparrman 1783
  • Lacerta nilotica Linnaeus 1766
  • Monitor elegans senegalensis Schlegel 1844
  • Monitor niloticus Lichtenstein 1818
  • Monitor pulcher Leach 1819
  • Stellio saurus Laurenti 1768
  • Tupinambis stellatus Daudin 1802
  • Varanus niloticus Martens 1942
  • Tupinambis elegans Daudin 1802
Nile monitor (varanus niloticus) distribution map.png
Nile monitor range

The Nile monitor (Varanus niloticus) is a large member of the monitor lizard family (Varanidae) found throughout much of Africa. Other common names include the African small-grain lizard,[2] water leguaan[3] or river leguaan (leguan, leguaan, and likkewaan mean monitor lizard in South African English, and can be used interchangeably).[4] Until 1997, the Nile monitor included the ornate monitor (V. ornatus) as a subspecies.[5]


Nile monitors can grow to about 120 to 180 cm (3 ft 11 in to 5 ft 11 in) in length, with the largest specimens attaining 244 cm (8 ft 0 in).[6][7] In an average-sized specimen, the snout-to-vent length will be around 50 cm (1 ft 8 in).[8] In body mass, adults have been reported to vary widely, one study claiming only 0.8 to 1.7 kg (1.8 to 3.7 lb), others state weights ranging from 5.9 to 15 kg (13 to 33 lb) in big monitors. Variations may be due to age or environmental conditions.[9][10][11] Exceptionally large specimens may scale as much as 20 kg (44 lb), but this species weighs somewhat less on average than the bulkier Varanus albigularis, the only other African lizard to rival the Nile monitor in size.[12] They have muscular bodies, strong legs, and powerful jaws. Their teeth are sharp and pointed in juvenile animals and become blunt and peg-like in adults. They also possess sharp claws used for climbing, digging, defense, or tearing at their prey. Like all monitors, they have forked tongues, with highly developed olfactory properties. The Nile monitor has quite striking, but variable, skin patterns, as they are greyish-brown above with greenish-yellow barring on the tail and large, greenish-yellow rosette-like spots on their backs with a blackish tiny spot in the middle. Their throats and undersides are an ochre-yellow to yellow-cream with some faint barring often on their throats.[12]

Their nostrils are placed high on their snouts, indicating these animals are highly aquatic. They are also excellent climbers and quick runners on land. Nile monitors feed on fish, snails, frogs, crocodile eggs and young, snakes, birds, small mammals, large insects, and carrion.


Nile monitors are native to Africa and the species is distributed throughout the entire central and southern regions of the continent, including Sudan and a portion of central Egypt along the Nile river. [13] They are not found in any of the desert regions of Africa, however, as they thrive around rivers. [14][15]

Invasive species[edit]

In Florida, established breeding populations of Nile monitors have been known to exist in different parts of the state since at least 1990. [16] The vast majority of the established breeding population of the species is in Lee County, Florida, particularly in the Cape Coral and surrounding regions, including the nearby barrier islands (Sanibel, Captiva, and North Captiva), Pine Island, Fort Myers, and Punta Rassa. Established populations also exist in adjacent Charlotte County, especially on Gasparilla Island.[15] Areas with a sizeable number of Nile monitor sightings in Florida include Palm Beach County just southwest of West Palm Beach along State Road 80.[17] In July 2008, a Nile monitor was spotted in Homestead, a small city southwest of Miami.[18] Other sightings have been reported near Hollywood, Naranja, and as far south as Key Largo in the Florida Keys.[17] The potential for the established population of Nile monitors in Lee, Charlotte, and other counties in Florida, to negatively impact indigenous crocodilians (American alligator Alligator mississippiensis and American crocodile Crocodylus acutus) is enormous given that they normally raid crocodile nests, eat eggs, and prey on small crocodiles in Africa. Anecdotal evidence indicates a high rate of disappearance of domestic pets and feral cats in Cape Coral. It also prey on other invasive species such as the Burmese Python egg nest[15]

In captivity[edit]

Nile monitors require experienced care as pets and are not recommended for beginners; nevertheless they are often found in the pet trade. Albino (amelanistic) specimens have been found and propagated in captivity.


  1. ^ IUCN Red List and search for Varanus niloticus
  2. ^ a b "Synonyms of Nile Monitor (Veranus nioloticus)". Encyclopedia of Life. Retrieved 15 December 2013. 
  3. ^ Varanus niloticus, The Reptile Database
  4. ^ Oxford Dictionaries. Oxford University Press Retrieved 17 December 2013.  Missing or empty |title= (help)
  5. ^ Böhme, W., & Ziegler, T. (1997). A taxonomic review of the Varanus (Polydaedalus) niloticus (Linnaeus, 1766) species complex. The Herpetological Journal 7: 155-162.
  6. ^ Nile Monitor Care Sheet
  7. ^ Enge, K. M., Krysko, K. L., Hankins, K. R., Campbell, T. S., & King, F. W. (2004). Status of the Nile monitor (Varanus niloticus) in southwestern Florida. Southeastern Naturalist, 3(4), 571-582.
  8. ^ "Varanus niloticus". Monitor Lizards – Captive Husbandry. Retrieved 15 December 2013. 
  9. ^ Condon, K. (1987). A kinematic analysis of mesokinesis in the Nile monitor (Varanus niloticus). Experimental biology, 47(2), 73.
  10. ^ Hirth & Latif 1979
  11. ^ "ANIMALS - Varanus niloticus". Dr. Giuseppe Mazza's Photomazza. Retrieved 2013-06-06. 
  12. ^ a b "Nile Monitors". L. Campbell's Herp Page. Retrieved 2013-06-06. 
  13. ^ (Schleich et al., 1996; Spawls et al., 2002).
  14. ^ Reptile Specialists (Nile monitor)
  15. ^ a b c "NAS - Invasive Species FactSheet: Varanus niloticus (Nile monitor)". Nonindenous Aquatic Species. Gainesville, FL: United States Geological Survey.  Unknown parameter |DUPLICATE_work= ignored (help)[dead link]
  16. ^ (Campbell, 2003; Enge et al. 2004).
  17. ^ a b Everglades CISMA
  18. ^ Hofmeyer, Erik (10 June 2008). "Homestead ARB home to diverse array of wildlife". Homestead Air Reserve Base News (Homestead Air Reserve Base). Retrieved 15 December 2013.