Varanus acanthurus
Silhouette: B Neale · PhyloPic
In 3 days ~30% in a week ~60%
The spiny-tailed monitor (Varanus acanthurus), also known as the Australian spiny-tailed monitor, the ridge-tailed monitor the Ackie dwarf monitor, and colloquially simply ackie monitor, is an Australian species of lizard belonging to the genus of monitor lizards (Varanus).
The spiny-tailed monitor, a somewhat small monitor lizard, can attain a total length of up to 70 cm (27 in), although there are unconfirmed reports of wild individuals growing up to 34 inches. The tail is about 1.3-2.3 times as long as the head and body combined. The upper side is a rich, dark brown and painted with bright-yellowish to cream spots, which often enclose a few dark scales. Its tail is round in section and features very spinose scales. There are 70-115 scales around the middle of the body.
The spiny-tailed monitor is distinguished from the similar-looking species V. baritji and V. primordius by the presence of pale longitudinal stripes on the neck. This arid-adapted lizard is found in northern Western Australia, in the Northern Territory and in the western and north-western parts of Queensland. The spiny-tailed monitor is associated with arid rocky... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Ningaloo Marine Park | 🇦🇺 Australia |
More parks will be added in future updates.
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Moscow Zoo | 🇷🇺 Russia | |
| 2 | National Zoological Park | 🇺🇸 United States | |
| 3 | Basel Zoo | 🇨🇭 Switzerland | |
| 4 | North Carolina Zoo | 🇺🇸 United States | |
| 5 | Zoobotánico Jerez | 🇪🇸 Spain | |
| 6 | Taronga Western Plains Zoo | 🇦🇺 Australia | |
| 7 | Bronx Zoo | 🇺🇸 United States | |
| 8 | Bratislava Zoo | 🇸🇰 Slovakia | |
| 9 | Sedgwick County Zoo | 🇺🇸 United States | |
| 10 | Omaha’s Henry Doorly Zoo and Aquarium | 🇺🇸 United States | |
| 11 | Kyiv Zoo | 🇺🇦 Ukraine | |
| 12 | Saint Louis Zoo | 🇺🇸 United States | |
| 13 | Currumbin Wildlife Sanctuary | 🇦🇺 Australia | |
| 14 | Melbourne Zoo | 🇦🇺 Australia | |
| 15 | ABQ BioPark Zoo | 🇺🇸 United States | |
| 16 | Cameron Park Zoo | 🇺🇸 United States | |
| 17 | Schönbrunn Zoo | 🇦🇹 Austria | |
| 18 | Zoo d'Amnéville | 🇫🇷 France | |
| 19 | Riverbanks Zoo | 🇺🇸 United States | |
| 20 | bioparco | 🇮🇹 Italy | |
| 21 | Plock Zoo | 🇵🇱 Poland | |
| 22 | Eskişehir Zoo | 🇹🇷 Türkiye | |
| 23 | Ménagerie du Jardin des Plantes | 🇫🇷 France | |
| 24 | Sacramento Zoo | 🇺🇸 United States | |
| 25 | Zoo de Córdoba | 🇪🇸 Spain | |
| 26 | Turtle Bay Exploration Park | 🇺🇸 United States | |
| 27 | Bali Bird Park | 🇮🇩 Indonesia | |
| 28 | Rodbaston Animal Zone | 🇬🇧 United Kingdom | |
| 29 | Vancouver Aquarium | 🇨🇦 Canada | |
| 30 | Sea Life Sydney Aquarium | 🇦🇺 Australia | |
| 31 | Exotarium Sosnowiec | 🇵🇱 Poland | |
| 32 | Wild Life Sydney | 🇦🇺 Australia | |
| 33 | National Aquarium | 🇺🇸 United States | |
| 34 | Aquarium d'Amnéville | 🇫🇷 France | |
| 35 | Dolphinarium in Odesa | 🇺🇦 Ukraine |
With luck
About 10% of wildlife watchers report a Ridgetail Monitor sighting in Ningaloo Marine Park on a given day, based on 5 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 26th most-seen of the 29 reptiles we can rate there. Over three days the chance rises to about 30%, and over a week to about 60%, if each day is a fresh chance.
August
In that month about 30% of wildlife watchers report a Ridgetail Monitor in Ningaloo Marine Park on a given day, against under 5% in September to May, the lowest months. That is one of Ningaloo Marine Park's driest months, with about 10 mm of rain against 50 mm in June.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Ridgetail Monitor sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Only Ningaloo Marine Park, in our data
Ningaloo Marine Park is the only park on Wallace's Line with enough records to rate Ridgetail Monitor sightings: about 10% of wildlife watchers there report one on a given day.
Same genus: Varanus
The closest relatives of the Ridgetail Monitor that you can see in Ningaloo Marine Park (genus Varanus, Monitor Lizards) are Perentie (about 20%) and Gould's Goanna (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Ridgetail Monitor is recorded against all the reptiles logged in Ningaloo Marine Park (5 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
