Roughneck monitor explained

The black rough-necked monitor (Varanus rudicollis) is a species of monitor lizard found in Southeast Asian countries of Thailand, Burma, and Malaysia. It is also found in Indonesia on Sumatra and islands of the Riau Archipelago^[1] It is sometimes known simply as the roughneck monitor.^[2] In Thailand is called h̄èā cĥāng (Thai: เห่าช้าง; "elephant bark").^[3]

The habitat of Varanus rudicollis is limited to primary and secondary rainforest and mangrove swamps.^[4] In the wild the black rough-necked monitor is very rarely seen, but whether this is because of its rarity or its very secretive behavior is uncertain. They are often kept successfully in captivity, but have a shy disposition.^[5]

This species is most closely related to its sister group, the water monitor species complex (e.g., the Asian water monitor) which are also in the subgenus Soterosaurus, having split from them 14 million years ago in the middle Miocene.^[6]

Description

The black roughneck is a medium to large monitor. It usually reaches an average adult size of 3–4 ft. (90–120 cm), with a maximum length of 5feet, reported. The black rough-necked monitor can be easily recognized by large pointed scales adorning the necks of adults. They are a gracile, long-bodied lizard with a prominently pointed snout. Black roughnecks are known for their very calm temperament, rarely biting or tail whipping in captivity. When threatened they prefer to escape, urinate or defecate, puff up their throats or “go necrotic” by closing their eyes as if playing dead.

Diet habits

The dietary habits of black rough-necked monitors have been the subject of various studies. Early research by Schnider (in Werner 1900) found insects in specimen from Sumatra. Mertens (1942) suggested that ants and possibly termites were a significant part of their diet, collected using their tongue. Auffenberg (1988) supported this by discovering termites, large stick insects, and tree centipedes in specimens from Malaysia. Brandenberg (1983) found a stomach full of large cockroaches and grasshoppers in one individual, while another from Surat Thani in Thailand had a stomach full of crabs (Nabhitabhata, pers. comm.). Further research by Losos and Greene (1988) revealed that the diet of V. rudicollis may include frogs and their eggs, spiders, scorpions, crabs, cockroaches, beetles, and orthopterans.^[7]

These monitors may remain active throughout the year, with their presence most noticeable during months of heavy rainfall

Lifespan

The known lifespan of black rough-necked monitor is about 10–20 years in captivity.^[5]

References

• (1992). Reproductive notes on the black roughneck monitor lizard (Varanus rudicollis Gray, 1845). VaraNews 3(2): 3.

Further reading

• Photos at Redtailboa.net
• Photos at Museumstuff.com
• Amer, Sayed A. M. and Yoshinori Kumazawa 2008. Timing of a mtDNA gene rearrangement and intercontinental dispersal of varanid lizards. Genes Genet. Syst. 83: 275–280
• Auliya, M. (2006). Taxonomy, Life History, and conservation of giant reptiles in west Kalimantan. Natur und Tier Verlag, Münster, 432 pp.
• Ávalos, J. de & Martínez Carrión, P. (1997). Warane Reptilia (Münster) 2 (5): 16-21
• Barbour, Thomas (1932). A new Bornean monitor Proceedings of the New England Zoological Club 13: 1-2
• Bayless, Mark K. 1997. The rough-neck Monitor lizard (Varanus rudicollis) Bulletin of the Chicago Herpetological Society 32 (12): 250-252
• Bennett, Daniel 1993. A review of some literature concerning the rough-necked monitor lizard Varanus rudicollis Reptilian 1 (9): 7-10
• Bennett, Daniel; Liat, Lim Boo 1995. A note on the distribution of Varanus dumerilii and V. rudicollis in Peninsular Malaysia. Malayan Nature Journal 49(2):113-116.
• Bong Heang, Kiew 1987. An annotated checklist of the herpetofauna of Ulu Endau, Johore, Malaysia Malayan Nature J. 41(2-3): 413-423.
• Boulenger, G.A. 1885. Catalogue of the lizards in the British Museum (Natural History). Vol. 2, Second edition. London, xiii+497 pp.
• De Rooij, N. de 1915. The Reptiles of the Indo-Australian Archipelago. I. Lacertilia, Chelonia, Emydosauria. Leiden (E. J. Brill), xiv + 384 pp.
• Gaulke, Maren 1991. Systematic relationships of the Philippine water monitors as compared with Varanus s. salvator, with a discussion of dispersal routes Mertensiella 2: 154-167
• Gray, J. E. 1845. Catalogue of the specimens of lizards in the collection of the British Museum. Trustees of die British Museum/Edward Newman, London: xxvii + 289 pp.
• Horn,H.G. & Peters,G. 1982. Beiträge zur Biologie des Rauhnackenwarans, Varanus (Dendrovaranus) rudicollis Gray. Salamandra 18 (1/2): 29-40
• MANGILI (1962). Giard. zool. Roma, 4: 30
• Manthey, U. & Grossmann, W. (1997). Amphibien & Reptilien Südostasiens. Natur und Tier Verlag (Münster), 512 pp.
• Taylor, E.H. 1963. The lizards of Thailand. Univ. Kansas Sci. Bull. 44: 687-1077.
• Werner, F. 1900. Reptilien und Batrachier aus Sumatra, gesammelt Herrn. Gustav Schneider jr., im Jahre 1897-1898. Zool.Jahrb. (syst) 13:479-508

Notes and References

1. Web site: Indonesiatraveling.com.
2. http://jcvi.org/reptiles/species.php?genus=Varanus&species=rudicollis JCVI.org
3. News: อ.เจษฎา เร่งแจง เห่าช้าง เป็นสัตว์กลุ่มตะกวด ไม่ใช่งู-ไม่มีพิษ. 12 June 2015. 16 June 2016. Kapook.com. Thai.
4. http://www.mampam.com/index.php?option=com_content&task=view&id=58&Itemid=84 Mampam.com
5. Web site: Herpcenter.com. dead. https://web.archive.org/web/20091031114945/http://www.herpcenter.com/roughneck-monitor-caresheet.html. 2009-10-31.
6. Welton . Luke J. . Wood . Perry L. . Oaks . Jamie R. . Siler . Cameron D. . Brown . Rafe M. . 2014-05-01 . Fossil-calibrated phylogeny and historical biogeography of Southeast Asian water monitors (Varanus salvator Complex) . Molecular Phylogenetics and Evolution . 74 . 29–37 . 10.1016/j.ympev.2014.01.016 . 24486878 . 1055-7903.
7. Daniel Bennett. 1995. A Little Book of Monitor Lizards. Viper Press U.K.