Ornamental snake (Denisonia maculata)

Classified as Vulnerable (VU) on the IUCN Red List (1).

The ornamental snake has a relatively stout body (3) (4) which is brown, greyish-brown or black in colour, with smooth scales. The underside of the body is white or cream, often with dark streaks or flecks on the outer edges, while the head is darker on top, with distinct bars on the lips (2) (3) (5). The male and female ornamental snake are similar in size (4). Like other members of the Elapidae family, a group that includes the cobras, mambas, sea snakes and coral snakes, the ornamental snake possesses enlarged, hollow fangs in the front of the mouth (6).

The ornamental snake is restricted to a small area of Queensland, Australia, where it is known only from the Brigalow Belt region, within the drainage system of the Fitzroy and Dawson Rivers (2) (3) (7)

The ornamental snake occurs in Brigalow (Acacia harpophylla) woodland growing on clay and sandy soils, as well as in riverine woodland and open forest. It shows a preference for moist areas, and usually shelters under fallen logs, under bark or in deep cracks in the soil (2) (3) (7).

The ornamental snake feeds almost exclusively on frogs, which it hunts at night around water and in damp areas (2) (3) (4). The species is viviparous, giving birth to between 3 and 11 young, which have a snout-vent length of around 12 centimetres at birth (4).

Regarded as a potentially dangerous species (3), the venom of the ornamental snake may cause loss of consciousness in humans (5). This snake shows a distinctive defence posture, depressing and inflating the body when threatened, and holding it in a series of stiff curves, before thrashing about and striking out if approached (3) (8). However, it is reported to bite only as a last resort (8). The ornamental snake is also capable of flattening the body when squeezing through narrow spaces (3).

Although the population and range of the ornamental snake are not known to have decreased, it is likely to be threatened by habitat loss as a result of habitat clearance, grazing, crop production and urban development (3) (7) (9). Introduced species such as foxes and cats may also pose a threat (9), and it is likely that the ornamental snake could be poisoned by ingesting the introduced cane toad (Bufo marinus) (3), which is abundant within its range and which it has been reported to hunt (2) (7).

The ornamental snake is known to occur in Dipperu National Park, Queensland, and may also occur in a number of other conservation areas such as Blackdown Tableland National Park and Castle Tower National Park, amongst others (7). The 1993 Action Plan for Australian Reptiles outlines a number of objectives and management actions for the species. These include increasing knowledge of the ornamental snake’s biology, ecology and distribution, ensuring that secure, viable populations are maintained within reserves, developing community awareness, and promoting and implementing land management practices that reduce the threats to the ornamental snake outside of reserves (3) (7).

To find out more about the ornamental snake and about reptile conservation see:

• Department of the Environment, Water, Heritage and the Arts. (2009) Denisonia maculata. In: Species Profile and Threats Database. Department of the Environment, Water, Heritage and the Arts, Canberra. Available at:
  http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=1193
• Queensland Government - Ornamental snake: 
  http://www.derm.qld.gov.au/wildlife-ecosystems/wildlife/az_of_animals/ornamental_snake.html
• International Reptile Conservation Foundation:
  www.ircf.org

• Snout-vent length: a standard measurement of body length of reptiles. The measurement is from the tip of the nose (snout) to the anus (vent), and excludes the tail.
• Viviparous: giving birth to live offspring that develop inside the mother’s body.

1. IUCN Red List (May, 2009)
   http://www.iucnredlist.org/
2. Department of the Environment, Water, Heritage and the Arts. (2009) Denisonia maculata. In: Species Profile and Threats Database. Department of the Environment, Water, Heritage and the Arts, Canberra. Available at:
   http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=1193
3. Queensland Government: Ornamental snake (May, 2009)
   http://www.derm.qld.gov.au/wildlife-ecosystems/wildlife/az_of_animals/ornamental_snake.html
4. Shine, R. (1983) Food habits and reproductive biology of Australian elapid snakes of the genus Denisonia. Journal of Herpetology, 17(2): 171 - 175.
5. Kellaway, C.H. (1934) The venom of the ornamented snake Denisonia maculata. Australian Journal of Experimental Biology and Medical Science, 12: 47 - 54.
6. Greene, H.W. (2000) Snakes: The Evolution of Mystery in Nature. University of California Press, Berkeley, California.
7. Cogger, H., Cameron, E., Sadlier, R. and Eggler, P. (1993) The Action Plan for Australian Reptiles. Australian Nature Conservation Agency, Canberra.
8. Johnson, C.R. (1970) Defensive displays in some Australian Denisonia (Serpentes: Elapidae). Herpetologica, 26(4): 516 - 520.
9. Australian Government: Biodiversity Assessment - Central Mackay Coast (May, 2009)
   http://www.anra.gov.au/topics/vegetation/assessment/qld/ibra-cmc-species-threats.html