|Inland taipan (fierce snake)|
(F. McCoy, 1879)
|Range of inland taipan (in red)|
The inland taipan (Oxyuranus microlepidotus), also commonly known as the small-scaled snake and fierce snake, is a species native to Australia and is regarded as the most venomous land snake in the world based on LD50 values in mice. It is a species of taipan belonging to the Elapidae family. Although highly venomous, it is very shy and reclusive, and always prefers to escape from threat (the word "fierce" from its alternative name describes its venom, not its temperament).
The inland taipan is dark tan, ranging from a rich, dark hue to a brownish light-green, depending on season. Its back, sides and tail may be different shades of brown and grey, with many scales having a wide blackish edge. These dark-marked scales occur in diagonal rows so that the marks align to form broken chevrons of variable length that are inclined backward and downward. The lowermost lateral scales often have an anterior yellow edge. The dorsal scales are smooth and without keels. The round-snouted head and neck are usually noticeably darker than the body (glossy black in winter, dark brown in summer), the darker colour allowing the snake to heat itself while only exposing a smaller portion of the body at the burrow entrance. The eye is of average size with a blackish brown iris and without a noticeable coloured rim around the pupil.
The inland taipan averages approximately 1.8 metres (5.9 ft) in total length, although larger specimens can reach total lengths of 2.5 metres (8.2 ft).
Inland taipans adapt to their environment by changing the colour of the skin during seasonal changes. They tend to become lighter during summer and darker during the winter. This seasonal colour change serves the purpose of thermoregulation, allowing the snake to absorb more light in the colder months.
The inland taipan is native to the arid regions of central to eastern Australia. Its range extends from the southeast part of the Northern Territory into west Queensland. The snake can also be found north of Lake Eyre and to the west of the split of the Murray River, Darling River, and Murrumbidgee River.
Diet and behaviour
The inland taipan consumes mostly rodents, other small mammals, and birds. Unlike other venomous snakes that strike with a single accurate bite then retreat to wait for the prey to die, the inland taipan is known to deliver up to seven venomous bites in a single attack.
Inland taipan produce clutches of between one and two dozen eggs. The eggs hatch two months later. The eggs are usually laid in abandoned animal burrows and deep crevices. Reproduction rate depends in part on their diet. If there is not enough food, then the snake will reproduce less.
The inland taipan's venom consists of Taipoxin and protease enzymes. The average quantity of venom delivered by this species is 44 mg and the maximum dose recorded is 110 mg. The median lethal dose (LD50) for mice is 2 μg/kg (ppb) for pure Taipoxin and 30 μg/kg (ppb) for the natural venom mixture. Its venom consists mostly of neurotoxins. Almost all positively identified inland taipan bite victims have been herpetologists handling the snakes for study, and all were treated successfully with antivenom—no recorded incidents have been fatal since the advent of the specific antivenom therapy.
- The Reptile Database. www.reptile-database.org.
- LD50, seanthomas.net (December 1999).
- "Our Animals – Reptiles – Venomous Snakes – Fierce Snake". Australia Zoo. Retrieved 2009-05-21.
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- Fohlman, J.; Eaker, D.; Karlsoon, E. and Thesleff, S. (1976). "Taipoxin, an extremely potent presynaptic neurotoxin from the venom of the australian snake taipan (Oxyuranus s. scutellatus). Isolation, characterization, quaternary structure and pharmacological properties". Eur. J. Biochem. 68 (2): 457–69. doi:10.1111/j.1432-1033.1976.tb10833.x. PMID 976268.
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- Barrett, Robyn; Mark Little (Oct–Dec 2003). "Five years of snake envenoming in far north Queensland". Emergency Medicine 15 (5–6): 500–510. doi:10.1046/j.1442-2026.2003.00509.x. PMID 14992068.
- White, Julian (November 1991). "Oxyuranus microlepidotus". Chemical Safety Information from Intergovernmental Organizations. Retrieved 24 July 2009.
- Boulenger, G.A. 1896. Catalogue of the Snakes in the British Museum (Natural History). Volume III., Containing the Colubridæ (Opisthoglyphæ and Proteroglyphæ),... Trustees of the British Museum. (Taylor and Francis, printers.) London. xiv + 727 pp. + Plates I.- XXV. (Pseudechis microlepidotus, p. 332.)
- McCoy, F. 1879. Natural History of Victoria. Prodromus of the Zoology of Victoria; or, Figures and Descriptions of the Living Species of All Classes of the Victorian Indigenous Animals. Decade III. G. Robertson, publisher. London. (J. Ferres, government printer. Melbourne.) 50 pp. + Plates 21-30. (Diemenia microlepidota, pp. 12-13 + Plate 23, Figures 2-3.)
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