The largest living lizard, found on five small Indonesian islands and nowhere else. It kills deer and buffalo with serrated, iron-edged teeth and a venomous bite, wears bone armour under its skin, and its females can lay fertile eggs without ever meeting a male.

Venom or bacteria?See the numbers
FamilyVaranidae (monitors)
Lives on5 Indonesian islands
IUCN statusEndangered
DietDeer, pigs, buffalo, carrion
KOMODO DRAGONS AT A GLANCE

The Komodo dragon (Varanus komodoensis) is a monitor lizard that lives on Komodo, Rinca, Flores, Gili Motang and Gili Dasami in eastern Indonesia. Adult males commonly reach about 2.5 m and 70 to 90 kg. It is an ambush predator and scavenger, the top carnivore on its islands, and adults eat young dragons, which spend their first years in trees. Its ancestors grew large in Australia several million years ago and reached Indonesia later. About 1,400 mature adults remain, and the species was listed as Endangered in 2021 because rising seas and warming are expected to shrink its habitat.

Figures graded and sourced in the fact sheet below.
KEY DISCOVERIES
1912NamedPeter Ouwens describes the species from animals collected on Komodo two years earlier.
1926Burden expeditionW. Douglas Burden brings live dragons to New York. The trip helps inspire King Kong.
1969A year on KomodoWalter Auffenberg moves his family to the island for the first long field study.
2006Virgin birthsTwo zoo females lay fertile eggs without mating (Watts et al.).
2009Venom glandsMRI scans show venom glands in the lower jaw (Fry et al.).
2024Iron teethThe cutting edges of the teeth are found to be coated in iron (LeBlanc et al.).
ONLY IN THE KOMODO DRAGON

What makes the Komodo dragon unlike any other animal?

Short answer: It is the only lizard that regularly kills prey many times its own weight, and it does so with a set of tools no other living reptile combines.

01The largest living lizardAdult males commonly reach 2.5 m. The largest wild animal on record was just over 3 m.Jessop et al. 2006
02Iron-edged teethAn orange layer rich in iron coats the serrations and tips, keeping the blades sharp.LeBlanc et al. 2024
03A venomous biteGlands in the lower jaw release toxins that lower blood pressure and slow clotting.Fry et al. 2009
04Virgin birthsFemales kept alone have produced healthy young. All such hatchlings are male.Watts et al. 2006
05Chain mail under the skinAdults carry small bones under the scales from head to tail, in four distinct shapes.Maisano et al. 2019
06A mammal-like engineIts genome shows changes in energy and heart genes that fit its unusual stamina for a reptile.Lind et al. 2019
FACT SHEET

How big is a Komodo dragon?

Short answer: Adult males are commonly about 2.5 m and 70 to 90 kg. The largest reliably measured wild animal was 3.04 m.

MeasuredEstimatedQuoted, unverified
LengthMeasuredup to ~3 mLargest wild3.04 mTypical male~2.3 to 2.6 mFemales are smaller, usually under 2.3 m. Jessop et al. 2006
WeightMeasured~40 to 90 kgWild adult male~70 to 90 kgZoo record166 kgThe 166 kg zoo animal was weighed with a full stomach
One mealEstimatedup to ~80% of body weightKomodo dragon~80%Lion~25%Field observations by Auffenberg 1981; rarely matched since
TeethMeasured~60, serratedTeeth in mouth~60Tooth length~2.5 cmCurved, blade-like and replaced throughout life. LeBlanc et al. 2024
Bite forceEstimatedweak for its sizeKomodo skull39 NCrocodile skull252 NComputer models of same-size skulls, saltwater crocodile for comparison. Fry et al. 2009
SprintEstimated~20 km/hShort burst~20 km/hHuman sprinter~37 km/hBrief dashes only; it relies on ambush
ClutchMeasured~20 eggsEggs~15 to 30Incubation7 to 8 monthsLaid in burrows or old megapode bird mounds
Mature adultsEstimated~1,380Mature adults~1,380With juveniles~3,450IUCN Red List assessment, 2021
Smells a carcassQuoted, unverified9.5 km awayOften quoted, but we could not trace it to a measurement. Field studies describe dragons arriving from a few kilometres.Popular claim
VENOM AND BITE

Is the Komodo dragon venomous?

Short answer: Yes, according to most researchers. The old idea that it kills with filthy, bacteria-laden saliva has not held up. How much the venom matters compared with the wounds themselves is still argued.

Read: Komodo dragon venom →
Deadly bacteriaNOT SUPPORTEDThe claimRotting meat in the mouth breeds bacteria that poison prey over days.Evidence forMany bacteria species were cultured from wild dragons’ saliva in the 1990s.AgainstCaptive dragons’ mouths carry ordinary bacteria, like other carnivores. Dragons clean their mouths after feeding.Goldstein et al. 2013
VenomSUPPORTED, DEBATEDThe claimGlands in the lower jaw ooze venom into the wound.Evidence forMRI shows the glands. Their toxins lower blood pressure and stop clotting in lab tests.AgainstCritics say the dose and its effect on large wild prey have not been measured.Fry et al. 2009
The wound itselfWELL SUPPORTEDThe claimBlade-like teeth cause massive bleeding and shock.Evidence forThe skull is built to pull back while biting, slicing like a serrated knife.NoteVenom and wounds work together: one opens the animal, the other keeps it bleeding.Moreno et al. 2008
TeethAbout 60 curved, serrated blades, edged with iron, hidden in thick gums that bleed when it feeds.
SkullLight and flexible. Its bite is weak, so the power comes from the neck and body pulling backwards.
Venom glandsSix compartments on each side of the lower jaw, opening between the teeth.
Buffalo and wallowsBitten buffalo retreat into stagnant water, where wounds can turn septic. Any infection likely comes from the water, not the bite.
HUNTING

How does a Komodo dragon hunt?

Short answer: By ambush. It waits beside a game trail, lunges at close range, and tears with a bite-and-pull. If the prey escapes, it follows.

Compare: Komodo Dragon vs Saltwater Crocodile →
01WaitIt lies motionless beside a trail, sometimes for hours.
02LungeA dash of a few metres, aimed at the legs, belly or throat.
03Bite and pullIt clamps on and hauls back, so the teeth saw through flesh.
04FollowWounded prey is tracked by scent, tongue flicking as it walks.
05FeedBig dragons eat first. It swallows huge chunks, bones and hooves included.
PreyTimor deer above all, then wild pigs and water buffalo. People brought all three to the islands.
SmellThe forked tongue carries scent to an organ in the roof of the mouth, sampling left and right to find direction.
CannibalismAdults eat young dragons. In one long study, juveniles made up about a tenth of adult diet.
ScavengingMuch of its food is carrion. A carcass can draw a dozen dragons.
Auffenberg 1981. Attacks on people are rare: Komodo National Park recorded 24 between 1974 and 2012, five of them fatal.
LIFE CYCLE

How do Komodo dragons reproduce?

Short answer: Females lay about 20 eggs a year in a burrow or an old bird mound. Hatchlings climb trees straight away and stay there for years, out of reach of adults.

May to AugMatingMales wrestle upright on their hind legs for access to females.
SeptemberEggsAbout 20 eggs, often dug into the nest mounds of megapode birds.
7 to 8 monthsIncubationThe female may guard the nest for the first months.
Mar to AprHatchingHatchlings are about 40 cm long and boldly patterned.
Years 1 to 4Life in treesYoung eat insects, geckos and eggs in the canopy until they are too heavy to climb.
Virgin birthIn 2006 two females in British zoos, one of which had never been kept with a male, laid eggs that hatched. Genetic tests confirmed the young had no father. Because of how sex is set in Komodo dragons, every such hatchling is male. A single female reaching an empty island could, in principle, found a population.Watts et al. 2006.
Slow to growSexual maturity at about 8 to 9 years.
LifespanAn estimated 30 years or more in the wild.
Armour comes lateHatchlings have no skin bones. They build up with age.
Rolling in dungYoung sometimes roll in droppings, which may put adults off eating them.
ISLANDS

Where do Komodo dragons live?

Short answer: On five islands in eastern Indonesia, in hot, dry savanna and monsoon forest below about 700 m. Four of the five are inside Komodo National Park.

Animal Map →
KomodoInside the national parkOne of the two main populations. The largest animals live here.
RincaInside the national parkThe other main population, at high density.
Gili MotangInside the national parkFewer than about 100, noticeably smaller-bodied, with less prey.
Gili DasamiInside the national parkA similar small, isolated group.
FloresMostly unprotectedScattered along the north and west coasts, and declining as land is cleared.
PadarLost in the 1970sDragons vanished after deer were poached out.
HomebodiesDragons can swim, yet tagged animals almost never leave the valley they hatched in, let alone the island. That keeps each population isolated and makes small ones fragile.Jessop et al. 2018; Purwandana et al. 2014.
EVOLUTION

Where did the Komodo dragon come from?

Short answer: Australia. Fossils show it was already full-sized there about 4 million years ago and spread to Indonesia later. It did not grow giant on its islands.

Read: monitor lizards →
TuataraLast of a separate reptile line, New ZealandGeckosAn early branch of lizardsSnakesLizards that lost their legsIguanas and chameleonsIguaniansGila monster and beaded lizardsVenomous cousins of the monitorsKomodo dragonVaranus komodoensis, a monitor lizardLizards and snakesVenom-gland groupAnguimorphs
Relationships simplified, not to time scale; the order of snakes and iguanians is debated. After Zheng & Wiens 2016. Outlines: PhyloPic, CC0.
MegalaniaIts extinct Australian relative, Varanus priscus, was far larger, perhaps 5 m or more, and died out roughly 50,000 years ago.
Closest living relativeThe lace monitor of eastern Australia, a tree-climbing lizard about 2 m long.
On Flores for a long timeKomodo-sized fossils on Flores go back about a million years, alongside dwarf elephants and, later, the small human Homo floresiensis.
Hocknull et al. 2009.
THREATS AND CONSERVATION

Are Komodo dragons endangered?

Short answer: Yes, since 2021. Numbers in the national park are stable, but the species lives on so little land that sea-level rise and warming could remove a large share of it.

Endangered register →
Climate and sea-level riseHIGHSuitable habitat is projected to shrink by at least 30% within about 45 years. Low valleys and coasts go first.
Habitat loss on FloresHIGHBurning and clearing for farms removes dry forest outside the park.
Prey poachingMEDIUMFewer deer means fewer and smaller dragons, as happened on Padar.
Conflict and tourismWATCHDragons take livestock near villages. Feeding and crowding by visitors changes behaviour.
Komodo National ParkFounded in 1980 and a UNESCO World Heritage Site since 1991. It holds most of the world’s dragons.
Trade banListed on CITES Appendix I, which bans international commercial trade.
Deer protectionAnti-poaching patrols protect the prey the dragons depend on.
Flores reserves and villagesSmall reserves on Flores, plus work with villagers to reduce livestock losses.
Zoo breedingA managed population in zoos worldwide acts as a back-up.
Jessop et al. (IUCN) 2021; Jones et al. 2020.
MYTH OR FACT

Six Komodo dragon claims, checked

3Myths1Half true2Facts
01MYTH“Komodo dragons kill with bacteria in their saliva.”WHERE IT CAME FROMWalter Auffenberg’s 1981 idea, repeated in documentaries for decades.
WHAT THE EVIDENCE SAYSCaptive dragons have ordinary mouth bacteria, and no study has shown bacteria from a bite killing prey. Blood loss, shock and venom explain the deaths.
WHAT IS TRUE INSTEADThe bite itself does the damage.Sources: 05
02MYTH“It became a giant because it lives on islands.”WHERE IT CAME FROMA 1987 idea that it grew large to hunt dwarf elephants on Flores.
WHAT THE EVIDENCE SAYSFossils from Australia show the same body size about 4 million years ago, before it reached Indonesia.
WHAT IS TRUE INSTEADA survivor of an age of giant lizards, not an island oddity.Sources: 07
03HALF TRUE“It can run as fast as a person.”WHERE IT CAME FROMGuidebooks and ranger warnings.
WHAT THE EVIDENCE SAYSIt reaches roughly 20 km/h in a short burst, enough to catch someone off guard, but it tires within seconds. A fit adult can outpace it over distance.
WHAT IS TRUE INSTEADFast for a few metres only.Sources: 01
04MYTH“Komodo dragons are deaf.”WHERE IT CAME FROMEarly observers saw no reaction to shouts.
WHAT THE EVIDENCE SAYSThey hear, though in a narrow range of roughly 400 to 2,000 Hz, and often simply ignore sound.
WHAT IS TRUE INSTEADLimited hearing, not none.Sources: 01
05FACT“They can swallow a goat whole.”WHERE IT CAME FROMField observations.
WHAT THE EVIDENCE SAYSLoose jaw joints and a stretchy throat let it gulp animals the size of a small goat, ramming them against a tree to force them down.
WHAT IS TRUE INSTEADTrue, for small goats and pigs.Sources: 01
06FACT“A lone female can have young.”WHERE IT CAME FROMZoo hatchings in 2006.
WHAT THE EVIDENCE SAYSGenetic tests showed hatchlings with no father. All were male.
WHAT IS TRUE INSTEADTrue: parthenogenesis.Sources: 03
OPEN QUESTIONS

What science still doesn’t know

?How much does the venom do?No one has measured how much venom enters a wild deer or buffalo, or how fast it acts.
?Why don’t they leave?Dragons swim well but almost never cross between islands or even valleys. The reason is unclear.
?How often are virgin births wild?Parthenogenesis is confirmed only in zoos. Whether it happens on the islands is unknown.
?Can they move uphill?If lowlands heat up or flood, it is not known whether dragons can shift to higher ground on Flores.
?What are the skin bones for?Protection from other dragons is the leading idea, but it has not been tested.
?How many are on Flores?The scattered Flores groups are the hardest to count and the least protected.
FAQ

Frequently asked questions

How big do Komodo dragons get?+

Adult males are commonly about 2.5 m long and 70 to 90 kg. The largest reliably measured wild animal was 3.04 m.

Are Komodo dragons venomous?+

Yes. Glands in the lower jaw produce venom that lowers blood pressure and slows clotting, though how much it contributes to kills is debated.

Where do Komodo dragons live?+

Only on five Indonesian islands: Komodo, Rinca, Flores, Gili Motang and Gili Dasami.

Do Komodo dragons attack people?+

Rarely. Komodo National Park recorded 24 attacks between 1974 and 2012, five of them fatal.

What do Komodo dragons eat?+

Mainly Timor deer, wild pigs, water buffalo and carrion. Adults also eat young dragons.

How many Komodo dragons are left?+

About 1,380 mature adults, or roughly 3,450 including juveniles. The species is Endangered.

COMPARE AND EXPLORE

Explore Komodo dragons further

COMPARISONKomodo Dragon vs Saltwater CrocodileOpen →TOPICMonitorsOpen →TOOLBite Force MeterOpen →TOOLSize ComparisonOpen →
HOW WE KNOW

Sources and how we check

This page is written by Strange Animals and checked against primary research. Every figure carries a grade and a numbered source.

Cite this pageStrange Animals. (2026, November 15). Komodo dragon (Varanus komodoensis): venom, hunting, islands and conservation. https://strangeanimals.info/reptiles/monitors/komodo-dragon
  1. 01Auffenberg, W. The Behavioral Ecology of the Komodo Monitor. University Presses of Florida1981
  2. 02Fry, B. G. et al. A central role for venom in predation by Varanus komodoensis (Komodo dragon) and the extinct giant Varanus (Megalania) priscus. PNAS 106: 8969-89742009
  3. 03Watts, P. C. et al. Parthenogenesis in Komodo dragons. Nature 444: 1021-10222006
  4. 04LeBlanc, A. R. H. et al. Iron-coated Komodo dragon teeth and the complex dental enamel of carnivorous reptiles. Nature Ecology & Evolution 8: 1711-17222024
  5. 05Goldstein, E. J. C. et al. Anaerobic and aerobic bacteriology of the saliva and gingiva from 16 captive Komodo dragons. Journal of Zoo and Wildlife Medicine 44: 262-2722013
  6. 06Moreno, K. et al. Cranial performance in the Komodo dragon as revealed by high-resolution 3-D finite element analysis. Journal of Anatomy 212: 736-7462008
  7. 07Hocknull, S. A. et al. Dragon’s paradise lost: palaeobiogeography, evolution and extinction of the largest-ever terrestrial lizards (Varanidae). PLoS ONE 4: e72412009
  8. 08Lind, A. L. et al. Genome of the Komodo dragon reveals adaptations in the cardiovascular and chemosensory systems of monitor lizards. Nature Ecology & Evolution 3: 1241-12522019
  9. 09Maisano, J. A. et al. The cephalic osteoderms of Varanus komodoensis as revealed by high-resolution X-ray computed tomography. The Anatomical Record 302: 1675-16802019
  10. 10Jessop, T. S. et al. Maximum body size among insular Komodo dragon populations covaries with large prey density. Oikos 112: 422-4292006
  11. 11Jessop, T. S. et al. Exploring mechanisms and origins of reduced dispersal in island Komodo dragons. Proceedings of the Royal Society B 285: 201818292018
  12. 12Purwandana, D. et al. Demographic status of Komodo dragons populations in Komodo National Park. Biological Conservation 171: 29-352014
  13. 13Jones, A. R. et al. Identifying island safe havens to prevent the extinction of the World’s largest lizard from global warming. Ecology and Evolution 10: 10492-105072020
  14. 14Jessop, T. S. et al. (IUCN) Varanus komodoensis. IUCN Red List. Endangered2021
  15. 15Zheng, Y. and Wiens, J. J. Combining phylogenomic and supermatrix approaches, and a time-calibrated phylogeny for squamate reptiles. Molecular Phylogenetics and Evolution 94: 537-5472016
WATCH

Three films worth your time

ClipThe Travel EditDragon IslandHow Komodo dragons stalk a water buffalo many times their own weight, then wait.Pairs with: Hunting →
Q&ABBC Earth KidsDo Komodo Dragons Eat People?A Komodo dragon keeper from Chester Zoo answers the most-searched questions, including whether they are venomous.Pairs with: Venom and bite →
Archive, 1956BBC Earth · Zoo Quest for a DragonAttenborough Catches a Komodo DragonA young David Attenborough films and traps a dragon on Komodo for London Zoo.Pairs with: Key discoveries →
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