Animal
Thorny devil
The thorny devil is a small, spiky lizard from the deserts of Australia. It eats only ants and can drink water through its skin.
The thorny devil is a small Australian desert lizard covered in spikes from head to tail. Despite its fierce name it is slow and harmless, it eats nothing but ants, and tiny channels in its skin carry water to its mouth.
Moloch horridus is a slow-moving agamid lizard of arid and semi-arid Australia and the only species in its genus. An ant specialist whose skin wicks water to the mouth by capillary action, it is common and widespread, and the IUCN lists it as Least Concern.
Photo: Emőke Dénes, CC BY-SA 4.0, via Wikimedia Commons
Meet the thorny devil
The thorny devil is a small lizard covered in spikes.
It looks fierce, but it is gentle and slow. It is about as long as a pencil, and it lives in the deserts of Australia.
The thorny devil is a lizard from the deserts of Australia, no longer than about 20 centimeters. Its body is covered with cone-shaped spikes and scales, even its tummy, and there is a spiky knob on the back of its neck.
Its name sounds scary, but the thorny devil is one of the calmest reptiles in the Australian outback. It moves slowly, eats only ants and is harmless to people. Its scientific name, horridus, means bristly.
Moloch horridus is an agamid lizard and the only species in its genus. Bush Heritage Australia gives a maximum length of about 20 centimeters; females are larger than males, and Animal Diversity Web gives a mass range of 28.5 to 57 grams. The large spines are boneless, apart from two supported by small bony bosses on the skull, and even the belly is covered in conical scales.
The thorny devil is often compared with the North American horned lizards. The two evolved separately into heavily armored, slow-moving ant specialists, a classic example of convergent evolution.
Quick facts
- Group
- Reptile
- Length
- up to 20 cm
- Weight
- 28.5 to 57 g
Where it lives
Thorny devils live only in Australia.
They live in hot, dry places with sand, spiky grass and bushes. They dig burrows to hide in.
Thorny devils live only in Australia, across most of its dry middle and west. You can find them in Western Australia, the southern half of the Northern Territory, most of South Australia and a small part of western Queensland.
They like sandy deserts, plains of spiky spinifex grass and dry scrub. In the hottest and coldest months they hide in burrows that they dig themselves.
The IUCN's 2017 assessment describes a range from the coast of Western Australia through the interior, including the southern half of the Northern Territory, most of South Australia and a small part of far-western Queensland. Some herpetologists argue that the range in Western Australia is not continuous from the coast to the interior, but experts consulted for the assessment consider it largely continuous.
It favors arid and semi-arid country with sand or sandy loam soils: sand and spinifex deserts, shrubland, and mallee and acacia woodland with plenty of debris. Part of its range lies in protected areas such as the Gibson Desert Nature Reserve.
Continent
Its habitat
Where can you find this animal?
- Lives here naturally · Countries and seas named by a scientific source
- Sightings recorded · Records of wild sightings (GBIF)
Lives here naturally · Countries and seas named by a scientific source
Arid and semi-arid sandy country across Western Australia, the southern half of the Northern Territory, most of South Australia and far-western Queensland. Thorny devils are not found in most of eastern Australia or in the tropical north.
Places: Australia.
Source: iucn-red-list · checked October 2026
Sightings recorded · Records of wild sightings (GBIF)
Counts of GBIF records of wild observations (human and machine) and preserved specimens. Records include introduced populations, vagrants, escaped or released animals and misidentifications, so a country with records is not necessarily part of the native range.
Wild sightings have been recorded in Australia.
Source: gbif · checked October 2026
Range maps show where scientists say an animal lives, often country by country. An animal may live in only part of a country shown, and sightings records can include animals that wandered far from home.
What it eats
Thorny devils eat only ants.
They sit beside an ant trail and lick up ants, one after another, with their short, sticky tongues.
Thorny devils eat ants and nothing else. In the morning and late afternoon a thorny devil finds a sheltered spot beside an ant trail and waits. As the ants march past, it laps them up one by one with its short, sticky tongue.
Ants are small and not very nourishing, so thorny devils eat a lot of them. Their stomachs are large, and one thorny devil can eat about a thousand ants in a single day.
The thorny devil is an obligate ant-eater (IUCN). Bush Heritage Australia describes it choosing a covered feeding site in the morning and late afternoon and lapping up ants from passing trails with a short, sticky tongue; its large stomach lets it eat about a thousand ants a day.
The skull and teeth are specialized too. Animal Diversity Web notes that lower teeth fit between pairs of upper teeth to make a shearing tool for hard-bodied ants, and that the front teeth have been lost, because the tongue, not the teeth, captures the prey.
Did you know?
Thorny devils change color during the day.
A thorny devil can be brown or olive in the cool morning and turn light yellow as the day warms up.
Skin color varies with temperature, from brown or olive in the morning to light yellow in the warmth of the afternoon (Animal Diversity Web).
Spikes that drink
The thorny devil's spikes protect it.
The spikes also help it drink! Tiny grooves in its skin carry water all the way to its mouth.
Spikes make a thorny devil hard for predators to eat. For a long time, scientists thought that was all the spikes were for.
Then they found something amazing. Between the scales are tiny channels, like very thin straws. When the lizard stands in a puddle or gets wet with dew, the water creeps along the channels to its mouth, and the devil gulps it in. It needs this trick, because its mouth is built for eating ants and cannot lap up water from a puddle.
Channels between the scales move water by capillary action to the mouth, where the lizard swallows it with jaw movements. Thorny devils cannot drink directly because the jaw and tongue are specialized for ants. In a 2016 study reported by ABC News, thorny devils standing in a puddle began drinking within about 10 seconds, but on damp sand their channels filled only partly; the researchers suggest they shovel damp sand onto their backs, letting gravity help fill the channels.
Color changes with temperature: Animal Diversity Web describes individuals as brown or olive in the morning and light yellow as the afternoon warms.
Growing up
A mother thorny devil digs a deep hole and lays her eggs.
She covers the hole up so nobody can find it. Months later, the tiny babies climb out.
Thorny devils mate and lay eggs from late winter to early summer, which in Australia is from August to December. The female digs a special burrow in the sand and lays 3 to 10 eggs, most often about 8. Then she fills it in and smooths the sand so the nest is hidden.
The eggs hatch three to four months later. The babies weigh less than 2 grams, about as much as a paper clip or two, and they climb out of the nest on their own. Females keep growing until they are about five years old.
Breeding is mainly in late winter to early summer (August to December), though mating has also been seen in autumn. Males approach females and bob their heads (Bush Heritage Australia adds leg-waving), and unreceptive females roll to throw a male off. Females dig a separate egg-laying burrow, up to 22 centimeters deep according to Animal Diversity Web, lay 3 to 10 eggs (IUCN gives a mode of 8), then backfill it and smooth the surface.
Incubation lasts 90 to 132 days (average 118). Hatchlings weigh about 1.8 grams and apparently eat their eggshell before climbing out. Females grow faster than males after their first year and keep growing until about five. The IUCN cites estimates that thorny devils live at least six years in the wild and up to 20 in captivity.
A slow, jerky walk
Thorny devils walk in a funny way.
They lift their tails and rock forward and back, step by step. Their colors help them hide in the sand.
A thorny devil walks very slowly, with its tail held up, rocking forward and backward with each jerky step. Scientists think this odd walk might confuse predators.
Its sandy colors make it very hard to spot, even for experts looking right at it. It also has a spiky knob on its neck that may act like a pretend head to put off predators. Its natural enemies include goannas and birds such as the brown falcon.
Activity is bimodal: Animal Diversity Web describes thorny devils as active in autumn (March to May) and from late winter to early summer (August to December), and almost inactive in burrows during the hottest (January to February) and coldest (June to July) months. They control body temperature partly by posture, pressing against warm ground or lifting the body away from it.
Defense combines camouflage, armor and behavior. The slow, rocking gait with the tail raised may confuse predators, and the spiny nuchal hump is thought to work as a false head (Bush Heritage Australia). Predators include goannas and brown falcons.
Did you know?
Thorny devils may pile damp sand onto their backs to get a drink.
Thorny devils have been seen shoveling damp sand onto their backs after rain. Scientists think this helps water soak into their skin channels so they can drink.
Experiments reported in 2016 suggest thorny devils cover themselves with damp sand, using gravity to help fill their skin channels, because standing on damp sand alone does not fill them.
Doing well, with care
There are lots of thorny devils in Australia.
They need healthy deserts full of ants. Sometimes they sit on warm roads, so drivers need to watch out for them.
Thorny devils are common across a huge area, so they are listed as least concern. They are not in danger right now.
But they depend completely on ants and on healthy desert. Changes to wildfires, animals brought in from other places and damaged land can harm local populations. Thorny devils also like to warm up on sunny roads, where cars can hit them. Some live in protected nature reserves.
The IUCN assessed the thorny devil as Least Concern in 2017, citing its very wide range, no identified major threats and a stable population. It notes some demand in the international pet trade, limited by the species' strict diet.
Bush Heritage Australia notes that its distribution and population size are still not well known, and that its reliance on ants and intact desert makes local populations sensitive to changed fire patterns, invasive species and habitat damage. Basking on warm road surfaces exposes it to traffic. It occurs in protected areas, including several Bush Heritage reserves and the Birriliburu Indigenous Protected Area.
IUCN Red List
How is the thorny devil doing in the wild?
- Least Concern (this animal)
- Near Threatened
- Vulnerable
- Endangered
- Critically Endangered
- Extinct in the Wild
- Extinct
Least Concern
Not at risk of disappearing from the wild right now.
See the IUCN Red List assessment · The IUCN Red List of Threatened Species 2022.2
Amazing facts
-
A thorny devil drinks through tiny grooves in its skin.
Tiny channels between a thorny devil's scales carry water to its mouth, like a bundle of very thin straws.
Capillary channels between the scales move water from wet surfaces or damp sand to the mouth, where the lizard swallows it.
-
A thorny devil can eat about a thousand ants in a day.
Ants are tiny, so a thorny devil eats a lot of them: about a thousand in one day.
Its large stomach lets it take about a thousand ants a day, compensating for the low nutritional value of ants (Bush Heritage Australia).
-
Thorny devils change color during the day.
A thorny devil can be brown or olive in the cool morning and turn light yellow as the day warms up.
Skin color varies with temperature, from brown or olive in the morning to light yellow in the warmth of the afternoon (Animal Diversity Web).
-
Thorny devils may pile damp sand onto their backs to get a drink.
Thorny devils have been seen shoveling damp sand onto their backs after rain. Scientists think this helps water soak into their skin channels so they can drink.
Experiments reported in 2016 suggest thorny devils cover themselves with damp sand, using gravity to help fill their skin channels, because standing on damp sand alone does not fill them.
Words to know
- spinifex
- a spiky grass that grows in Australia's dry inland
- capillary action
- the way water creeps along very narrow spaces by itself
- camouflage
- colors or patterns that help an animal blend in
- specimen
- a real animal or object kept so people can study it
- predator
- an animal that hunts other animals for food
- arid
- very dry, with little rain
Discovery challenge
-
What does a thorny devil eat?
What is the only food a thorny devil eats?
What does the thorny devil's diet consist of?
- Leaves
- Ants
- Fish
Show the answer
Ants
Thorny devils eat only ants.
They eat only ants, lapping them up from ant trails with a sticky tongue.
It is an obligate ant-eater, taking about a thousand ants a day.
-
How does a thorny devil get water to its mouth?
How does a thorny devil get a drink?
How does water reach a thorny devil's mouth?
- Through tiny channels in its skin
- By licking puddles with its tongue
- By eating snow
Show the answer
Through tiny channels in its skin
Tiny grooves in its skin carry water to its mouth.
Channels between its scales carry water to its mouth. Its mouth is built for ants and cannot lap up water.
Interscale channels move water by capillary action to the mouth; its jaw and tongue cannot drink directly.
-
Where do thorny devils live?
In which country do thorny devils live in the wild?
Which country is the thorny devil native to?
- Brazil
- Canada
- Australia
Show the answer
Australia
Thorny devils live in Australia.
They live only in Australia, in its dry middle and west.
It is endemic to arid and semi-arid Australia.
-
What is the spiky knob on a thorny devil's neck for?
What might the spiky knob on a thorny devil's neck do?
What is thought to be the role of the thorny devil's nuchal hump?
- It may look like a pretend head to fool predators
- It stores water
- It helps it fly
Show the answer
It may look like a pretend head to fool predators
It may look like a second head and fool hungry animals.
Scientists think the knob may act like a pretend head that puts predators off.
The spiny nuchal hump is thought to function as a false head that deters predators.
Places where you might see it
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Watch
Country
Australia
Australia is a country and the smallest continent, surrounded by ocean in the Southern Hemisphere. Much of its middle is dry and flat, most people live near the coast, and its animals include kangaroos, koalas and the platypus, a mammal that lays eggs.
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Watch
Natural wonder
Uluru
Uluru is a huge sandstone rock in the desert of central Australia, rising 348 meters above the plain, with a base 9.4 kilometers around. The Anangu are its Traditional Owners, and the national park around it is run by Anangu and Parks Australia together.
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For parents & teachers
What children will learn
- Describe how the thorny devil's spines and skin channels help it survive in the desert.
- Explain what capillary action is, using the thorny devil as an example.
- Describe the thorny devil's ant diet and life cycle.
- Understand that a museum specimen is a real animal preserved for study.
Recommended ages: 3 to 17 · About 15 minutes
Talk about it
- Why might an animal that cannot lick up water need another way to drink?
- How could being slow and spiky be a good way to stay safe?
- Why do museums keep preserved animals, and what can we learn from them?
Try at home or in class
- Dip the corner of a paper towel into a glass of colored water and watch the water climb up by itself: that is capillary action, the same idea the thorny devil uses.
- Hold two smooth plastic rulers close together at one edge and touch them to water to see it creep up the narrow gap.
Key vocabulary: spinifex, capillary action, camouflage, specimen, predator, arid
Where these facts come from
- The IUCN Red List of Threatened Species , International Union for Conservation of Nature (IUCN terms of use (no redistribution of Red List data or range maps))
- GBIF Backbone Taxonomy and GBIF Occurrence Search , Global Biodiversity Information Facility (CC0 1.0 (backbone); occurrence counts are facts derived from records under CC0, CC BY and CC BY-NC)
- Moloch horridus (Thorny Devil), global Red List assessment 2017 , IUCN Red List of Threatened Species
- Thorny Devils , Bush Heritage Australia
- Moloch horridus (thorny devil) , Animal Diversity Web, University of Michigan Museum of Zoology
- Australia's thorny devils drink water by burying themselves in sand , ABC News (Australian Broadcasting Corporation)
- Wikidata , Wikimedia Foundation (CC0 1.0)
- Wikimedia Commons , Wikimedia Foundation (Per file: Public domain, CC0, CC BY or CC BY-SA only (credited on each page))
Checked, not yet human-reviewed. Last updated October 27, 2026. Spotted a mistake? Tell us.