Reptilia · Squamata
Moloch horridusGray, 1841
Thorny Devil
Photograph by Bäras (talk · contribs), CC BY-SA, via Wikimedia Commons
A ground-dwelling, day-active, meat-eating lizard from the Australo-Pacific region, reaching 122 mm snout to vent.
Also called Mountain Devil.
Reptilia › Squamata › Agamidae › Moloch
- Grows to
- 122mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Diurnal
- Lives up to
- 20years
Longer than 71% of all agamids anyone has measured.
The bar is the rank itself: its length is the share of the family this animal exceeds. The chart below is the family’s real spread, on a logarithmic scale because body length here runs from 32 to 418 mm. The solid rule is this animal. Every bar is a count of real species, and nothing on this figure is estimated.
What is known
44 sourced facts, each taken from a named scientific dataset. How to read these.
Cited from a dataset unless a row is marked otherwise.
Standing in the world
- Still living
- Extant
- Conservation status
- Least Concern
- Status assessed · the year the Red List last looked
- 2017
- Population trend
- Stable
The animal itself
- Limbs
- Four legs
- Venomous
- No
- Fangs
- None
- Longest recorded life
- 20years
- Preferred body temperature · chosen in a laboratory gradientmeasured
- 36.7°C
- Body temperature when active · measured in the wild
- 32.9°C91 °F
- Body temp in the wild · mean, when active
- 31.7–34.1°C89–93 °F
Slavens and Slavens 1999: 3.33; Greer 2005: 12 years and 10 months as adult, so at least 13 and 10; at least 6 in nature and 8 in captivity, likely reach 20 (Pianka and Pianka 1970), 6-20 (Pianka et al. 1998)
mean body temperature of active individuals in nature
body temperature of active animals in nature
Size
- Length snout to vent · greatest recorded
- 122mm4.75 in
- Length snout to vent · adult female mean
- 106.2mm4.25 in
- Largest female · snout to vent
- 106.2mm4.25 in
- Hatchling length · snout to vent
- 34.5mm1.25 in
- Largest juvenile · snout to vent
- 34.5mm1.25 in
- Body mass · greatestcomputed
- 61.97g2.2 oz
- Body mass at hatchingmeasured
- 2.78g0.1 oz
max 122 mm SVL (Feldman et al. 2016)
snout-vent length; the source column mixes this with straight carapace length
computed from length by a family-level allometric equation, not weighed
How it lives
- Diet
- Carnivorous
- How it hunts
- Sit and wait
- Active
- Diurnal
- Where it lives
- Terrestrial
- Habitat
- Desert, Shrubland
- Biome
- Deserts & Xeric Shrublands
- Active season · months of the year
- 8months
- Region
- Australo-Pacific
- Mainland or island
- Mainland
- Highest it lives · above sea level
- 550m
- Range size
- 3,199,445km²
- Home range · largest recorded
- 56.25m2
insects (mostly ants, e.g., Abensperg-Traun and Steven 1997), almost only ants (Pianka and Pianka 1970), insectivorous (Lazzari et al. 2022)
(e.g., Mesquita et al. 2016) "classic sit and wait" (Pianka et al. 1998)
e.g., Pianka et al. 2017, Black 1983, Lazzari et al. 2022
e.g., Mesquita et al. 2016, Gray et al. 2019, Tallowin et al. 2019
Breeding
- Reproduction
- Oviparous
- Average clutch
- 7.25eggs
- Eggs or young per clutch
- 3–10eggs
- Mean clutch
- 6.5–8eggs
- Clutches in a year
- 1per year
- Clutches a year
- 1–2per year
- First breeds at
- 12–36months
3-10, mode 8 (Pianka and Pianka 1970), mean 6.8 (Pianka 2014), mean 6.79 (Mesquita et al. 2016), 6-7 (Melville and Wilson 2019)
Naming and history
- Suborder
- Sauria
- Infraorder
- Acrodontia
- Subspecies
- No
- Described by
- Gray
- Moved to another genus · since it was first described
- No
- Described in
- 1841
- Type locality
- Australia
Keeping one
19 in × 19 in × 12 in(49 × 49 × 31 cm)
Minimum length × width × height, for one animal. Bigger is always better.
The standard sizes ground-dwelling species at 4 × 4 × 2.5 times snout-vent length.
Mindestanforderungen an die Haltung von Reptilien (Sachverständigengutachten), German Federal Ministry for Nutrition, Agriculture and Forestry, Animal Welfare Division, 10 January 1997. The standard states these floor areas are recommendations rather than binding limits.
From this animal’s own snout-vent length of 4.75 in (122 mm), at 4 × 4 × 2.5 times it, following the German federal welfare standard — how this is worked out.
In a laboratory thermal gradient this species settled at 98 °F (36.7 °C).
Preferred body temperature, recorded in a laboratory gradient where the animal could choose freely. A measurement of the animal, not a setting for a thermostat.
Feeding
A prey item should be no wider than the space between the animal's eyes.
Widely used across reptile husbandry references. The stated reason is that the gap approximates the width of the throat, so wider prey is associated with impaction. This is established practice, not a measurement.
8kJ per day
Worked out for an animal of 62 g, the heaviest recorded for Thorny Devil — so it is the top of the range, not a figure for a particular animal. Weigh yours and the number will be lower.
An upper estimate, not a feeding target, and not veterinary advice. The equation covers only what an animal burns staying alive, so a growing, gravid or recovering animal needs more — and it was measured on wild animals, which move far more than one in an enclosure. Body condition and a vet who knows the species are what a feeding decision should rest on. Where this comes from.
What nobody knows
These are not gaps in our research. No scientific dataset records them for this species — and saying so is information you cannot get from a reference that simply leaves a field out.
- — Length snout to vent · adult male mean
- — Length snout to vent · adult mean
- — Length nose to tail · greatest recorded
- — Female length · mean, nose to tail
- — Length nose to tail · adult male mean
- — Length nose to tail · adult mean
- — Largest male · snout to vent
- — Largest female · shell length
- — Largest male · shell length
- — Hatchling length · nose to tail
- — Largest juvenile · shell length
- — Egg length
- — Egg width
- — Body mass · a typical adult
- — Body mass · adult female, mean
- — Eats arthropods
- — Eats vertebrates
- — Eats plant matter
- — How the young develop
- — Gestation or incubation
- — Hatchling length · smallest recorded
- — Hatchling length · largest recorded
- — Age at first breeding · female
- — Mature from · youngest recorded
- — Mature by · oldest recorded
- — Size at maturity · smallest recorded
- — Size at maturity · largest recorded
- — Colour on the back
- — Pattern on the back
- — Pupil
- — Sex decided by
- — Red List criteria
- — Density · lowest recorded
- — Density · highest recorded
- — Active in
- — Lowest it lives · above sea level
Others in Agamidae
Take this data
Everything on this page is available as data under CC BY 4.0 — use it freely, credit it, no permission needed.
This species as JSON · the whole dataset
Cite this page
The Reptile & Amphibian Encyclopedia (2026). Moloch horridus. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/moloch-horridus
@misc{moloch_horridus_2026,
title = {Moloch horridus},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/moloch-horridus}
}Sources
- Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
- Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.
- Catalogue of Life (dataset 3LR), used under CC BY.