National Aquarium – Spiny-tailed monitor

Spiny-Tailed Monitor

Varanus acanthurus

National Aquarium – Spiny-tailed monitor National Aquarium – Spiny-tailed monitor National Aquarium – Spiny-tailed monitor National Aquarium – Spiny-tailed monitor

The spiny-tailed monitor, also known as the ridge-tailed monitor or spiny-tailed "goanna," exists in a number of sizes and colors throughout northwestern Australia.

The spikes ring the tail, directed backward from the body, making it difficult to pull the monitor from a rocky crevice where it may be hiding. The tail is also useful in hunting, as the lizard can whip it around as a large, spiky club to attack prey.

Though this species can be highly variable in color and pattern, red and yellow are the two distinct forms. Here at the National Aquarium, visitors can see the red phase spiny-tailed monitor, noted by its distinct brick-red color accented with dark and cream ringed spots.

Did You Know?

This monitor uses its tail to wedge itself into tight crevices.


Spiny-tailed monitors are carnivores with a voracious appetite. Juveniles in the wild feed on insects, while adults feed primarily on smaller reptiles and mammals. We offer our monitors a variety of insects and small rodents weekly, allowing guests the opportunity to observe their feeding behavior.


The maximum length of the spiny-tailed monitor is approximately 2 feet, although size varies with region.


The spiny-tailed monitor is native to the northwestern part of Australia, in habitats ranging from tropical escarpment to red sand deserts.

Population Status

The spiny-tailed monitor is common within its range.


Raptors, snakes and other monitors all prey on the spiny-tailed monitor, consuming adults, juveniles and eggs.

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