savannah monitor
{{Short description|Species of lizard}}
{{Speciesbox
| name = Savannah monitor
| image = Savannah monitor in the glass case.jpg
| image_caption = Adult in captivity
| image2 = Varanus exanthematicus in the wild.jpg
| image2_caption = Wild individual
| status = LC
| status_system = IUCN3.1
| genus = Varanus
| parent = Varanus (Polydaedalus)
| species = exanthematicus
| authority = (Bosc, 1792)
}}
The savannah monitor (Varanus exanthematicus) is a medium-sized species of monitor lizard native to Africa. The species is known as Bosc's monitor in Europe, since French scientist Louis Bosc first described the species.{{cite book | last = Bosc | first = Louis | title = Lacerta exanthematica | publisher = Act. Soc. Hist. Nat. Paris 1| page = 25 }} It belongs to the subgenus Polydaedalus.
Etymology
The specific name exanthematicus is derived from the Greek word exanthem {{IPAc-en|ɛ|k|ˈ|s|æ|n|θ|ɪ|m}}, meaning an eruption or blister of the skin.{{cite book |editor1-last=Simpson |editor1-first=JA |editor2-last=Weiner |editor2-first=ESC |title=Oxford English Dictionary |publisher=Clarendon Press |year=1989 |location=Oxford, England}} French botanist and zoologist Louis Augustin Guillaume BoscBeolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. {{ISBN|978-1-4214-0135-5}}. ("Bosc", p. 32). originally described this lizard as Lacerta exanthematica in reference to the large oval scales on the back of its neck.
The species was formerly known as Lacerta exanthematicus.{{cite web |last1=Kaplan |first1=Melissa |title=Savannah Monitors |url=http://www.anapsid.org/savannah.html |website=www.anapsid.org}}
Description
Savannah monitors are stoutly built, with relatively short limbs and toes, and skulls and dentition adapted to feed on hard-shelled prey. They are robust creatures, with powerful limbs for digging, powerful jaws and blunt, peglike teeth. Maximum size is rarely more than 100 cm.
The skin coloration pattern varies according to the local habitat substrate. The body scales are large, usually less than 100 scales around midbody, a partly laterally compressed tail with a double dorsal ridge and nostrils equidistant from the eyes and the tip of the snout.{{cite book | last = Bennett | first = Daniel |author2=Ravi Thakoordyal | title = The Savannah Monitor, the Truth about Varanus exanthematicus | publisher = Viper Press| year = 2003 | location = UK| isbn = 0-9526632-9-5| page = 84 }}
File:Varanus exanthematicus skull (cropped).png
The savannah monitor is often confused with the white-throat monitor (Varanus albigularis), which can grow to lengths of 5–6 ft. While similar in overall appearance, this species possesses significant morphological and ecological differences and is recognized as a very distinct species.
Behaviour
=Diet=
File:Savannah Monitor Skull.png
Their diet is much more restricted than that of other African monitor lizards, consisting mainly of snails, crabs, scorpions, millipedes, centipedes, orthopterans, mantids, hymenopterans, lepidopterans, beetles and other invertebrates, as well as frogs.Herpetological Journal, Vol. 10, pp. 75-96 (2000) Preliminary Data on the Diet of Juvenile Varanus exanthematicus (SAURIA: VARANIDAE) In the Coastal Plain of Ghana. Daniel Bennett. Department of Zoology, University of Aberdeen. https://web.archive.org/web/20131127140535/http://library.mampam.com/bennett2000dietofvaranusexanthematicus.pdf{{cite web | url=https://biocyclopedia.com/index/monitor_lizards/varanus_exanthematicus.php | title=Varanus Exanthematicus }} Information about the diet of savannah monitors in the wild has been recorded in Senegal and Ghana.{{cite journal |last1= Cisse|first1= M|year= 1972|title=L'alimentaire des Varanides au Senegal|journal= Bulletin l'Institute Fond. Afr. Noire.|volume= 34|pages=503–515 }}{{cite book |last=Bennett |first=Daniel |editor-first=Eric R. |editor-last=Pianka |title=Varanoid Lizards of the World |publisher=Indiana University Press |year=2004 |pages=95–103 |chapter=Chapter 5.2: Varanus exanthematicus |isbn=0-253-34366-6}}{{cite journal |last1= Bennett|first1= Daniel|year= 2000|title=Preliminary data on the diet of juvenile Varanus exanthematicus in the coastal plain of Ghana|journal= Herpetological Journal|volume= 10|pages=75–76 }} It feeds almost exclusively on arthropods and molluscs. In Senegal, Julus millipedes were the most common prey of adults; in Ghana, small crickets formed the bulk of the diet of animals less than 2 months old; orthopterans (especially Brachytrupes), scorpions and amphibians were the most common prey of animals 6–7 months old. Many adults also consume large quantities of snails. Full grown V. exanthematicus have teeth that are quite blunt to help them crack and eat snails. The jaw has evolved to put maximum leverage at the back of the jaw to crush snail shells. Adults will also eat carrion if they come across it.{{Cite web|url=https://animaldiversity.org/accounts/Varanus_exanthematicus/|title=Varanus exanthematicus (Savannah Monitor)|website=Animal Diversity Web }} Wild savannah monitors are also known to occasionally eat lizard eggs (such as those of agamids and their own kind).{{cite web | url=https://reptilesupply.com/blogs/monitor-lizards/what-can-my-savannah-monitor-eat | title=What Can My Savannah Monitor Eat? | date=22 November 2021 }}{{cite web | url=https://biocyclopedia.com/index/monitor_lizards/varanus_exanthematicus.php | title=Varanus Exanthematicus }}
=Reproduction=
Females dig a deep hole in the substrate, in which up to 40 or more eggs are laid, which hatch after about 156–160 days. Hatchlings start feeding a few days after the yolk sac has been absorbed, which may take 12 days or more after hatching.{{Cite journal|last=Coiro|first=Jarret|date=August 2007|title=Captive Breeding of Varanus exanthematicus|journal=Biawak|volume=1|issue=1|pages=29–33}}
In captivity
File:Savannah Monitor (141593814).jpg
The savannah monitor is the most common monitor lizard species available in the pet trade, accounting for almost half (48.0552%) of the entire international trade in live monitor lizards. Monitoring the Trade: Using the CITES Database to Examine the Global Trade in Live Monitor Lizards (Varanus spp.) ANGELO P. PERNETTA. BIAWAK. 2009. https://www.academia.edu/7931146/Monitoring_the_Trade_Using_the_CITES_Database_to_Examine_the_Global_Trade_in_Live_Monitor_Lizards_Varanus_spp Despite its prevalence in global pet trade, successful captive reproduction is very rare, and a high mortality rate is associated with the species. Mampam Conservation. Facts and Fiction about Savannah Monitors. Bennett. https://web.archive.org/web/20171214182359/http://www.mampam.com/index.php?option=com_content&task=view&id=172&Itemid=87
Adult specimens frequently become unwanted pets and are reported as being the most common monitor lizards by animal rescue agencies. The skins are traded within the international leather trade and originate mainly from Chad, Mali and Sudan.{{citation needed|date=May 2018}}
Range
Its range extends throughout sub-Saharan Africa from Senegal east to Sudan and south almost to the Congo River and Rift Valley, where they are replaced by V. albigularis. V. exanthematicus is primarily a ground-dwelling species that shelters in burrows, although it is sometimes found in bushes or low trees. In the coastal plain of Ghana, V. exanthematicus juveniles are often associated with the burrows of the giant cricket Brachytrupes.{{cite journal |last1= Bennett|first1= Daniel|year= 2000|title=Observations of Bosc's monitor lizard (Varanus exanthematicus) in the wild|journal= Bulletin of Chicago Herpetological Society|volume= 35|pages=177–180 }}
Threats
V. exanthematicus is listed as least concern by IUCN. The species is hunted for its leather and meat, and for the international pet trade. The trade in wild collected savannah monitors is not of a global conservation concern, due to the vast range of the species; in addition to the collection for the pet trade often occurring over a relatively small area.{{cite web |url=http://www.mampam.com/index.php?option=com_content&task=view&id=173&Itemid=87 |url-status=dead |archive-url=https://web.archive.org/web/20160405130236/http://www.mampam.com/index.php?option=com_content&task=view&id=173&Itemid=87 |archive-date=2016-04-05 |title=Mampam Conservation - Savannah Monitors Lizards are Not Captive Bred}} An average of 30,574 live specimens were imported into the US each year, between 2000 and 2009; total imports of live specimens into the US between 2000 and 2010 was 325,480 animals. During the same period, 1,037 skins, shoes, and products of the species were imported into the US. Trade in live animals comes mainly from Ghana (235,903 animals exported between 2000 and 2010), Togo (188,110 animals exported between 2000 and 2010), and Benin (72,964 animals exported between 2000 and 2010). During the same period, total worldwide declared exports of skins and products of the species totalled 37,506.{{cite web|url=http://www.unep-wcmc-apps.org/citestrade/novice.cfm?CFID=49683141&CFTOKEN=77487601|title=CITES Trade Database|publisher=CITES|access-date=5 April 2012}}{{dead link|date=March 2018 |bot=InternetArchiveBot |fix-attempted=yes }} However, substantial undeclared trade in the species occurs from Sudan, Nigeria, and elsewhere. Within several West African nations, roadside diners and food stands specialize in “monitor stew”, a hot simmered dish of local vegetables and savannah monitor; it is unclear whether the cooked lizards are hunted or bred specifically for human consumption, or at what rate they are being killed for this purpose.{{cite web|url=https://www.youtube.com/watch?v=0inw7epdNNc |title=Savannah monitors in the wild (are we keeping them correctly?) |date=11 June 2022 |accessdate=3 March 2023 |author=Kaufman, Dav |website=YouTube}}
References
{{Reflist|2}}
Further reading
- {{cite journal|doi=10.1163/156853800507499|title=The density and abundance of juvenile Varanus exanthematicus (Sauria: Varanidae) in the coastal plain of Ghana|journal=Amphibia-Reptilia|volume=21|issue=3|pages=301–306|year=2000|last1=Bennett|first1=Daniel|doi-access=free}}
- Bennett, Daniel; Thakoordyal, Ravi (2003). The Savannah Monitor Lizard: the truth about Varanus exanthematicus. Glossop, England: Viper Press. 84 pp. {{ISBN|978-0952663294}}.
- {{author missing|date=November 2017}} (1993). "The Savanna Monitor (Varanus exanthematicus) in Africa and in your home". The Iowa Herpetological Society, June: 2-4 (Reprinted in International Reptile Breeders Association (IRBA), Monitor 1 (2): 10–12, 1994).
External links
{{Wikispecies|Varanus exanthematicus}}
{{Commons|Varanus exanthematicus}}
- [http://www.reptilespark.com/home/varanus/4.htm Photo of a Savannah monitor.]
- Savmon.org [https://web.archive.org/web/20191001123127/http://savmon.org/] Modern captive and known ecological information about Varanus exanthematicus.
{{Varanoidea}}
{{Taxonbar|from=Q135677}}
{{DEFAULTSORT:Savannah monitor}}
Category:Reptiles described in 1792