Ackies Monitor

ZOO LOCATION: Scutes Family Gallery

Lifespan: 20+ years

Wild Diet: Diet primarily insects and other lizards

Zoo Diet: Crickets and mealworms.

Predators: Predators include raptors, snakes and other monitors


IUCN Status: Not Evaluated

Zoo Location: Bird and Reptile House

Habitat/Range: Drier regions and arid deserts of northwestern Australia and South Australia.

Characteristics: Also called spiny-tailed monitor, these small scaled, short limbed monitors have round, thick tails that are covered in large, spiny keeled scales. Their coloring is variable but consists of a pattern of hollow rosettes that form rough rows dorsally. Their tail is less than 1.8 times the snout vent length. Total size from 1.6 to 2.3 feet. Background color varies from rusty to chocolate brown with yellow, cream or grayish ocelli (eye spots) on the back. Lips are generally pale, often white. Tongue is long, slender and forked like a snake’s. Belly is cream or whitish without dark markings. Nostril is small, round, and located midway between the snout tip and front edge of the eye. Upper head scales are small, numerous, and relatively smooth. Limbs are comparatively short. Breeders recognize a yellow and a red phase for this species

Behavior: Diurnal. Sexing is difficult. Sexing is accomplished by feeling for a sub-dermal horn or knob, located to either side of the vent (cloaca) under enlarged spiny scales, found only in males. Females may also have slightly enlarged post-cloacal scales and broad heads, characters generally ascribed to males, but not the calciferous knobs. Males also have a more developed, muscular neck region. Females have a more slender head that may be more pointed. Excavate burrows under larger rocks and defend territory with the spiny tails (which may also retard water loss). Rock crevices or burrows under large boulders serve as retreats and areas where animals may thermoregulate without being exposed to predators. Flat body and spiny tail are perfectly evolved for living in burrows and cracks. Able to fill itself with air to avoid being extracted, while spiny tail serves to cover more vulnerable exposed body parts. Streamlined shape makes living in burrows much easier, especially in groups. Smaller monitors species may live in colonies while larger monitor species are solitary.

Reproduction: Mates in the late dry season from August to November. Clutch size ranges from 2 to 11 eggs and is dependent upon the size of the female. Eggs are laid in an S-shaped tunnel that is filled with soft earth. Eggs measure roughly 1.2 in. Hatchlings emerge during the wet season from Dec. to March after a three to four month incubation period. May multi-clutch. Sex determination is dependant on temperature. May reach sexual maturity very quickly and have been known to lay fertile clutches as young as 5 or 6 months. Often mature by one year. Rarely exceeds 30 inches.

Conservation: This montior has not been evaluated by the IUCN and wild populations seem to be stable.