Varanus exanthematicus

Varanus exanthematicus (*)

Cladus: Eukaryota
Supergroup: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Classis: Reptilia
Subclassis: Diapsida
Infraclassis: Lepidosauromorpha
Superordo: Lepidosauria
Ordo: Squamata
Subordo: Sauria
Infraordo: Platynota
Familia: Varanidae
Genus: Varanus
Species: Varanus exanthematicus

Name

Varanus exanthematicus Bosc, 1792

Synonyms

* Lacerta exanthematicus BOSC 1792
* Varanus ocellatus DUMÉRIL & BIBRON 1836

Reference

* Varanus exanthematicus Report on ITIS
* FA Bisby, YR Roskov, MA Ruggiero, TM Orrell, LE Paglinawan, PW Brewer, N Bailly, J van Hertum, eds (2007). Species 2000 & ITIS Catalogue of Life: 2007 Annual Checklist. Digital resource at www.catalogueoflife.org/annual-checklist/2007/. Species 2000: Reading, U.K.[1]

Vernacular Name
Internationalization
Deutsch: Steppenwaran
English: Savannah Monitor
Polski: Waran stepowy
中文: 草原巨蜥

The savanna monitor (Varanus exanthematicus) is a species of monitor lizard native to Africa. The species is known as Bosc's Monitor in Europe, since a French scientist named Louis Bosc first described the species.[1] It belongs to the subgenus Polydaedalus along with the Nile Monitor, the Ornate Monitor and other monitors.


Etymology

The generic name Varanus is derived from the Arabic waral (ورل), which translates as "monitor" in English. The specific name exanthematicus is derived from two Greek words: exanthema meaning 'eruption' and mata meaning 'idle'.[citation needed] French botanist and Zoologist Louis Augustin Guillaume Bosc originally described this lizard as Lacerta exanthematicus in reference to the large oval scales on the back of the neck.[2]

Description

The savanna monitor has powerful limbs for digging and climbing, very powerful jaws that can easily crush bone and very strong, sharp teeth. Maximum size is usually 4 feet and rarely more than 5 feet in length. The pattern on the back of Varanus exanthematicus is uniformely grey to pale yellow.[3] The monitor has a short box-like head and large dorsal and nuchal scales.[2] Its short tail is round and stores fat as an energy reserve.[2]

Defense

The savanna monitor typically defends itself with its strong bite and powerful jaws. Its thick hide makes it resistant to most animal bites and herpetologist Robert Sprackland claims that the lizard is immune to most snake venom.[2] When confronted by a snake or other large predator the monitor rolls onto its back and grasps a hind leg in its mouth forming a ring with its body and making itself harder for the animal to swallow whole.[2] Savanna monitors, like most monitors, will expand their throat and body. They also will gape and let out a slow, deep hissing sound when threatened.

Diet

The savannah monitor are usually carnivorous but the occasional savannah monitor in captivity will eat plants, vegetables, and fruit, its preferred diet consists of small mammals, insects, eggs, birds, and dead animal remains. The feeding response of a savannah monitor is very aggressive. They find and track prey by using their Jacobson's organ which is located in the roof of their mouths. The Jacobson's organ is a secondary olfactory sense organ for many animals including reptiles. Once a savannah monitor senses food it goes into an overdrive. These monitors have such an appetite they will eat themselves to death if provided the chance.

Pet owners of savannah monitors also feed their monitor insects, fish, chicken, beef, and turkey as well as eggs and occasionally fruit/vegetables.

Range

Its range extends throughout sub-Saharan Africa from Senegal to Eritrea and northern Zaire.[2][4] V. exanthematicus is primarily a ground dwelling species that shelters in burrows, although they are sometimes found in bushes or low trees. In the coastal plain of Ghana, juvenile V. exanthematicus are often associated with the burrows of the giant cricket Brachytrupes.

Threats

The species is hunted for its leather and meat. The skins of the species are important in the international leather trade and originate mainly from Chad, Mali and Sudan. In 1984, the skins of over 1,000,000 dead savanna monitors were exported for the leather trade as opposed to a mere 900 live specimens for the pet trade.[2]

In captivity

This species is readily available in the pet trade. Savannah monitors can be very tame and docile if you work with them while they are babies. Juvenile animals are collected from several countries in West Africa (mainly Ghana, Togo, Benin and Nigeria) and exported worldwide. Animals sold as "captive bred", "captive farmed" or ranched are most often the offspring of gravid females collected during the breeding season.The eggs are later incubated by exporters. However, Savanna Monitors have been bred in captivity with some degree of regularity. Adult specimens sometimes become unwanted pets due to their large size. Caution needs to be taken in the care because these monitors live upwards of 10-12 years in captivity. The great majority of these animals are fed a rodent only diet and are not given sufficient basking and exercise areas for digestion of such meals. Furthermore, pet savannah monitors are given wildly insufficient humidity levels. These monitor lizards become dehydrated and/or obese, lethargic, and usually die early due to illness, liver complications, or even stress from overhandling.[5]

The savanna monitor is often confused with the whitethroat monitor (Varanus albigularis) which can grow to lengths of 1.5–2 m (4 ft 10 in–6 ft 7 in).

Further reading

* Bennett, D. 2000. The density and abundance of juvenile Varanus exanthematicus (Sauria: Varanidae) in the coastal plain of Ghana. Amphibia-Reptilia 21(3): 301–306.
* Bennett, D. 2000. Preliminary data on the diet of juvenile Varanus exanthematicus (Sauria: Varanidae) in the coastal plain of Ghana. Herpetological Journal 10(2): 75–76.
* Bennett, D, and R. Thakoordyal. 2003. The savanna monitor lizard: the truth about Varanus exanthematicus. Viper Press, Glossop. 2003: 1–83.
* Bennett, D, and R. Thakoordyal. 2003. The savanna monitor lizard: the truth about Varanus exanthematicus. Viper Press, Glossop. 2003: 17–18.
* 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):1 0-12, 1994).


References

1. ^ Obst, Fritz Jurgen; Richter, Klaus & Udo, Jacob (1988). Completely Illustrated Atlas of Reptiles and Amphibians for the Terrarium. TFH Publications. p. 830. ISBN 0866229582.
2. ^ a b c d e f g Robert George Sprackland (1992). Giant lizards. Neptune, NJ: T. F. H. Publications. ISBN 0-86622-634-6.
3. ^ Monitor-lizards.net
4. ^ Honoluluzoo.org
5. ^ Savannahmonitor.org

Images

Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License

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