Varanus acanthurus
The spiny-tailed monitor (Varanus acanthurus), also known as the ackie monitor, is a small, arid-adapted Australian lizard characterized by its spiny tail and distinctive yellow or cream spots on a dark brown body. It inhabits rocky ranges and outcrops across northern Australia, where it is a diurnal, solitary ground-dweller.
Key Facts
- ›Attains a total length of up to 70 cm (27 in).
- ›Possesses a round tail with very spinose scales.
- ›Found in arid rocky ranges and outcrops in northern Australia.
- ›Primarily feeds on arthropods, supplemented by small lizards and marsupial joeys.
- ›Diurnal and typically solitary ground-dwellers, often sheltering under rocks or in burrows.
- ›Clutches can contain up to 18 eggs, with incubation lasting three to five months.
Australian Spiny-Tailed Monitor, Ridge-Tailed Monitor, Ackie Dwarf Monitor, Ackie Monitor
Northern Western Australia, Northern Territory, Western Queensland, Eastern Queensland
Arid Rocky Ranges, Arid Rocky Outcrops
- Somewhat Small Monitor Lizard, Attaining A Total Length of Up To 70 cm .
- Tail Is Round In Section and Features Very Spinose Scales.
- Upper Side Is A Rich, Dark Brown, Painted With Bright-Yellowish To Cream Spots That Often Enclose A Few Dark Scales.
- Possesses Pale Longitudinal Stripes On the Neck, Distinguishing It From Similar Species.
- 70-115 Scales Around the Middle of the Body.
Arthropods, Small Lizards, Marsupial Joeys
- Diurnal
- Typically Solitary Ground-Dwellers
- Shelter Under Rock Slabs, Wedged Among Boulders, In Rock Crevices, and In Burrows
- Intensive Foragers, Likely Spending Significant Time Hunting
About Varanus acanthurus
Varanus acanthurus: The Spiny-Tailed Monitor
The spiny-tailed monitor, scientifically known as Varanus acanthurus and often called the ackie monitor, is a distinctive lizard species native to the arid regions of northern Australia. This arid-adapted reptile is characterized by its spiny tail, which is round in cross-section, and its coloration, typically a rich dark brown adorned with bright yellowish to cream spots. It is a relatively small monitor lizard, capable of reaching up to 70 cm (27 inches) in total length.
Distribution and Habitat
Varanus acanthurus is found across northern Australia, extending from the west coast of Western Australia through the Northern Territory and into parts of Queensland. It thrives in harsh, arid environments, specifically associating with rocky ranges and outcrops. These lizards often seek shelter within rock crevices, under rock slabs, or in burrows, utilizing these spaces to access humid microclimates essential for their survival in otherwise dry conditions.
Ecology and Diet
Spiny-tailed monitors are diurnal and generally solitary creatures. Their behavior suggests they are active foragers, spending considerable time hunting for food. Their diet is diverse, primarily consisting of arthropods such as grasshoppers, beetles, spiders, and snails. They also supplement their diet with small lizards, including skinks and geckos, and occasionally consume marsupial joeys. A significant portion of their water requirement, approximately 70%, is met through their food.
Reproduction
Reproduction in Varanus acanthurus involves females depositing eggs in burrows they excavate themselves, and there is evidence of communal nesting in large burrows by females in the wild. In captive environments, clutches can consist of up to 18 eggs, with incubation periods typically lasting between three to five months. Information regarding their reproductive cycle in natural settings is less extensively documented.
Source: Wikipedia ↗
Frequently Asked Questions
What are the common names for Varanus acanthurus?
Varanus acanthurus is known by several common names, including the spiny-tailed monitor, Australian spiny-tailed monitor, ridge-tailed monitor, and the ackie dwarf monitor. It is also colloquially referred to simply as the ackie monitor.
What does the spiny-tailed monitor look like?
This lizard typically has a dark brown upper side patterned with bright yellowish to cream spots. Its tail is round in cross-section and covered in very spinose scales, and it can reach a total length of up to 70 cm (27 inches).
Where is the spiny-tailed monitor found?
The spiny-tailed monitor is native to northern Australia, inhabiting arid rocky ranges and outcrops. Its distribution covers parts of Western Australia, the Northern Territory, and Queensland.
What does Varanus acanthurus eat?
Its diet primarily consists of arthropods such as grasshoppers, beetles, spiders, and snails. It also preys on small lizards like skinks and geckos, and occasionally marsupial joeys. About 70% of its water intake comes from its food.
What are the typical behaviors of the spiny-tailed monitor?
Spiny-tailed monitors are diurnal and generally solitary ground-dwellers. They are often found sheltering under rock slabs, within rock crevices, or in burrows, which provides access to humid microclimates.
How does the spiny-tailed monitor reproduce?
Reproduction involves females laying eggs in self-dug tunnels, sometimes communally in large burrows. In captivity, a clutch can consist of up to 18 eggs, which hatch after three to five months of incubation.
Are there different types of ackie monitors?
In the pet trade, two common 'variants' are recognized: the 'red ackie' and the 'yellow ackie'. The 'red ackie' is likely the subspecies Varanus acanthurus acanthurus, while the 'yellow ackie' is likely Varanus acanthurus brachyurus. The red ackie is generally larger and less common.
Related Lizards
Ablepharus
Ablepharus, commonly known as snake-eyed skinks, are small lizards distinguished by fused eyelids that prevent blinking, similar to snakes. They inhabit dry fields, hills, and rocky areas, often concealed within leaf litter. These skinks possess shiny, bronze scales and a characteristic dark stripe along their sides, feeding primarily on small insects and mollusks.
Acanthocercus atricollis
The black-necked agama, Acanthocercus atricollis, is a species of tree agama found across East, Central, and southern Africa. These lizards are known for forming structured colonies and are often found in high densities near human settlements due to reduced predator presence. They are primarily insectivorous ambush predators.
Agama agama
The common agama, also known as the red-headed rock agama, is a widespread lizard species native to sub-Saharan Africa and introduced to Florida. It is characterized by its distinct coloration, with males exhibiting blue bodies and yellow tails, while females and subordinates have olive green heads. These lizards are diurnal, territorial, and primarily insectivorous, playing an important role in their ecosystems.