Varanus gouldii

REPTILIA: SQUAMATA: VARANIDAE: Varanus
Varanus gouldii (Gray, 1858) *The name Varanus gouldii* officially conserved by ICZN Opinion 1948 (see "Type specimen" section below). Gould’s monitor/Sand monitor** (in Australia, the term "goanna" usually replaces "monitor") Photos & text by Dr. Robert George Sprackland. Specimen at right photographed in scrub at Yathong nature Preserve, NSW, Australia, October 1999.
Range: Much of Australia except the far south and forested regions.
Diagnosis: A medium to large varanid (up to 1.2 m) characterized by a laterally compressed tail with a solid yellow distal quarter, acute snout with nostril near tip, and no spots on the belly in adults. The tongue is pink.
Description: Snout acute, depressed at tip. Nostril small, round, and near snout tip. Canthus rostralis acute. Scales on top of head small, rounded and smooth. Supraoculars subequal or slightly smaller than interoculars. Prominent pre- and postocular streaks. Dorsum brown with distinct yellow spots or rosettes that form broken bands. Tail laterally compressed at least for its distal two-thirds, with a pair of low dorsal keels. Tail with thin, yellow bands, and a solid yellow distal tip.
Natural History: A wide-ranging and generalist species found in deserts, scrublands, and along forest fringes. Though alert and wary, they will allow rather close approach prior to fleeing.
Reproduction: One of the species that may lay eggs in termite mounds.
Taxonomy & Relationships: The sand monitors and their relatives are fairly well studied members of a group of similar species. Other members of the complex include Varanus panoptes, V. rosenbergi and V. spenceri. Two subspecies are recognized. 1) Varanus gouldii gouldii from the western half of Australia in arid environments; and 2) V. g. flavirufus is a spectacular gold and orange-marked form in which the light spots bleed together into large blotches, from the central deserts.
Variation: A variable species, in which the hue and intensity of the dorsal markings ranges from cream to yellow to orange, depending upon locality and age. Juveniles tend to be much more intensely colored than adults, with lemon yellow flanks. Additionally, juveniles of the Australian taxa often have a large gray throat marking and black flecks on the throat and anterior underside. Adults from the western half of Australia may have a background color that is dark brown to black, while eastern populations tend to have brown or reddish-brown coloring.
Additional Comments: This species is often confused with the Argus monitor (Varanus panoptes), from which it differs most notably in having a yellow tail tip, no black circles forming dorsal bands, and a more slender build. Unlike the Argus monitor, which will frequently assume a tripod position to look over tall objects, Gould’s monitors rarely, if ever, employ such behavior.
Type Specimen: A Neotype was proposed in 1997 and is presently awaiting approval by the International Commission on Zoological Nomenclature (ICZN). The taxonomic problem concerns an error in ascertaining which specimen in the British Museum collection was used by Gray when he described the species. The specimen believed to have been the type (ergo, lectotype) has been shown to have been acquisitioned too late to qualify. In March 2000 the ICZN ruled on a petition by R. Sprackland, H. Smith and P. Strimple to conserve the name Varanus gouldii as traditionally used. For details, see the Bulletin of Zoological Nomenclature 57(1): 63-65, Opinion 1948. The neotype is BMNH 1997.1, Karrakatta, Perth, Western Australia.
Literature: Click on a book to order a copy Bennett, Daniel. 1998. Monitor lizards: Natural history, biology & husbandry. Edition Chimaira. ISBN: 3-930612-10-0. Cogger, Harold. 1999. Reptiles and amphibians of Australia. 6th edition. Ralph Curtis Books. ISBN: 0-88359-048-4. Cogger, Harold. 1995. Reptiles and amphibians of Australia. 5th edition. Ralph Curtis Books. ISBN: 0-8014-2739-8. Cogger, Harold. 1984. Australian reptiles in colour. Revisede edition. Reed Books. ISBN: 0-7301-0043-X. Ehmann, Harald. 1992. Encyclopedia of Australian animals: Reptiles. Angus & Robertson. ISBN: 0-207-17379-6. Eidenmüller, Bernd. 1997. Warane: Lebensweise, Pflege, Zucht. Herpeton, Offenbach. In German. ISBN: 3-9802892-7-3. Greer, Allen. 1989. The biology & evolution of Australian lizards. Surrey Beatty & Sons. ISBN: 0-949324-21-3. Hoser, Raymond. 1989. Australian reptiles & frogs. Pierson & Co. ISBN: 0-947068-08-2. King, Dennis and Brian Green. 1999. Monitors: the biology of varanid lizards. 2nd edition. Krieger Publishing. ISBN: 1-57524-112-9. Sprackland, Robert. 2001. Savannah & Grassland Monitors. Advanced Vivarium Systems. ISBN: 1-882770-53-6. Sprackland, Robert. 1992. Giant Lizards. TFH Publications. ISBN: 0-86622-634-6. Thompson, Graham. 1996-97. Goannas in the graveyard. Australia Nature 25(7): 30-37. Thompson, Graham. 1994. Activity area during the breeding season of Varanus gouldii (Reptilia: Varanidae) in an urban environment. Wildlife Resources 21: 633-641. Weigel, John. 1988. Care of Australian reptiles in captivity. Australian Reptile Keepers Association. ISBN: 0-7316-3290-7.