ISSN 2398-2985  

Spiny-tailed monitor


Vetstream Ltd

Kirsty Dewhurst

Synonym(s): Varanus acanthurus, Ridge-tailed monitor, Ackies dwarf monitor


Scientific Classification

  • Kingdom: Animalia. 
  • Phylum: Chordata. 
  • Class: Reptilia. 
  • Order: Squamata. 
  • Family: Varanidae. 
  • Genus: Varanus.
  • Species: acanthurus

Distribution and habitat

  • Found in Australia, predominantly Western Australia, the Northern Territory and parts of Queensland. 
  • Mainly found in arid/dry temperatures, along rocky ranges and scrublands.

Species status

  • Common and not currently under threat. 
  • Current predators include snakes, raptors, other monitors and humans. 

Life span

  • Around 15-20 years.


  • Carnivorous. 
  • In the wild, they eat mainly insects and other small lizards, as well as small mammals, birds and bird eggs Lizard nutrition
  • In captivity, they should be fed insects, with the possible addition of other foods such as egg and turkey. 


  • Two subspecies can be identified: 
    • V. a. acanthurus (Red ackies): northwestern range of Australia. 
    • V. a. brachyurus (Yellow ackies): eastern range of Australia. 
  • There is little difference between these two subspecies.


  • Females lay clutches of up to 18 eggs Lizard reproduction
  • Incubation period of 3-5 months. 
  • Up to 6 clutches can be laid per year. 

As pets

  • Can be kept as pets, but research into the species is advised.

Predatory behavior

  • Sit-and-wait predators, ie they will wait for prey to become readily available. 

Biological Data

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Further Reading


Refereed papers

Other sources of information

  • Evolution Reptiles (2018) Spiny Tailed Monitor Varanus acanthurus. Website: Last accessed 28th February 2018. 
  • Monitor Lizards (2018) Health & Illness. Website: Last accessed 28th February 2018. 
  • National Aquarium/Aqua (2018) Spiny-Tailed Monitor. Website: Last accessed 28th February 2018. 
  • Reptiles Magazine (2018) Spiny-Tailed Monitor Lizard Care Tips. Website: Last accessed 28th February 2018. 
  • Shea G & Cogger H (2018) Varanus acanthurus. In: The IUCN Red List of Threatened Species. Website: Last accessed on 26 July 2018.
  • Madison Area Herpetological Society (2017) Ridge Tailed Monitor (Varanus [Subgenus Odatria] acanthurus). Website: Last accessed 25th July 2018.
  • Angell Pets (2015) Ackie Monitors Varanus acanthurus. Website: Last accessed 28th February 2018. 
  • Tait N et al (2015) The Encyclopedia of Reptiles Amphibians & Invertebrates. Red Lemon Press, UK. pp 58.
  • Reptile Zone Care Sheet for Monitors. Website: Last accessed 28th February 2018. 

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