The Komodo dragon
) is a large species of
lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang and
Gili Dasami. A member of the monitor lizard family (Varanidae), it is the
largest living species of lizard, growing to a maximum of length 3 metres
(9.8 ft) in rare cases and weighing up to around 70 kilograms (150 lb).
Their unusual size has been attributed to island gigantism, since there are
no other carnivorous animals to fill the niche on the islands where they live.
However, recent research suggests that the large size of komodo dragons may
be better understood as representative of a relict population of very large
varanid lizards that once lived across Indonesia and Australia, most of which,
along with other megafauna, died out after the Pleistocene.
Fossils very similar to V. komodoensis have been found in Australia
dating to greater than 3.8 million years ago, and its body size remained stable
on Flores, one of the handful of Indonesian islands where it is currently found,
over the last 900,000 years, "a time marked by major faunal turnovers,
extinction of the island's megafauna, and the arrival of early hominids by 880
Have you seen the Komodo
Dragon for real and what do you think of this incredible
Have your say
As a result of their size, these lizards dominate the ecosystems in which
they live. Komodo dragons hunt and ambush prey including invertebrates, birds,
and mammals. Their group behaviour in hunting is exceptional in the reptile
world. The diet of big Komodo dragons mainly consists of deer, though they also
eat considerable amounts of carrion.
Mating begins between May and August, and the eggs are laid in September.
About twenty eggs are deposited in abandoned megapode nests or in a self-dug
nesting hole. The eggs are incubated for seven to eight months, hatching in
April, when insects are most plentiful. Young Komodo dragons are vulnerable and
therefore dwell in trees, safe from predators and cannibalistic adults. They
take about eight to nine years to mature, and are estimated to live for up to 30
Komodo dragons were first recorded by Western scientists in 1910. Their large
size and fearsome reputation make them popular zoo exhibits. In the wild their
range has contracted due to human activities and they are listed as vulnerable
by the IUCN. They are protected under Indonesian law, and a national park,
Komodo National Park, was founded to aid protection efforts.
The Komodo dragon is also known as the Komodo monitor or the Komodo
Island monitor in scientific literature, although this is not very common.
To the natives of Komodo Island, it is referred to as ora, buaya darat
(land crocodile) or biawak raksasa (giant monitor).
The evolutionary development of the Komodo dragon started with the Varanus
genus, which originated in Asia about 40 million years ago and migrated to
Australia. Around 15 million years ago, a collision between Australia and
Southeast Asia allowed the varanids to move into what is now the Indonesian
archipelago, extending their range as far east as the island of Timor.
The Komodo dragon was believed to have differentiated from its Australian
ancestors 4 million years ago. However, recent fossil evidence from Queensland
suggests that the Komodo dragon evolved in Australia before spreading to
Indonesia. Dramatic lowering of sea level during the last glacial period
uncovered extensive stretches of continental shelf that the Komodo dragon
colonized, becoming isolated in their present island range as sea levels rose
Komodo dragon as
seen in Ragunan Zoo, Jakarta, Indonesia
In the wild, an adult Komodo dragon usually weighs around 70 kilograms
(150 lb), although captive specimens often weigh more. The largest verified wild
specimen was 3.13 metres (10.3 ft) long and weighed 166 kilograms (370 lb),
including undigested food.
The Komodo dragon has a tail as long as its body, as well as about 60
frequently replaced serrated teeth that can measure up to 2.5 cm (1 inch) in
length. Its saliva is frequently blood-tinged, because its teeth are almost
completely covered by gingival tissue that is naturally lacerated during
feeding. This creates an ideal culture for the virulent bacteria that live in
its mouth. It also has a long, yellow, deeply forked tongue.
The Komodo dragon does not have an acute sense of hearing, despite its
visible earholes, and is only able to hear sounds between 400 and 2000 hertz. It
is able to see as far away as 300 metres (980 ft), but because its retinas only
contain cones, it is thought to have poor night vision. The Komodo dragon is
able to see in color, but has poor visual discrimination of stationary objects.
The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as
with many other reptiles, with the vomeronasal sense using the Jacobson's organ.
With the help of a favorable wind and its habit of swinging its head from side
to side as it walks, Komodo dragons may be able to detect carrion from
4–9.5 kilometres (2.5–6 mi) away. The dragon's nostrils are not of great use for
smelling, as the animal does not have a diaphragm.
It only has a few taste buds in the back of its throat. Its scales, some of
which are reinforced with bone, have sensory plaques connected to nerves that
facilitate its sense of touch. The scales around the ears, lips, chin, and soles
of the feet may have three or more sensory plaques.
The Komodo dragon was formerly thought to be deaf when a study reported no
agitation in wild Komodo dragons in response to whispers, raised voices, or
shouts. This was disputed when London Zoological Garden employee Joan Proctor
trained a captive specimen to come out to feed at the sound of her voice, even
when she could not be seen.
The Komodo dragon prefers hot and dry places, and typically lives in dry open
grassland, savanna, and tropical forest at low elevations. As an ectotherm, it
is most active in the day, although it exhibits some nocturnal activity. Komodo
dragons are solitary, coming together only to breed and eat.
They are capable of running rapidly in brief sprints up to 20 kilometres per
hour (12.4 mph), diving up to 4.5 metres (15 ft), and climbing trees
proficiently when young through use of their strong claws. To catch prey that is
out of reach, the Komodo dragon may stand on its hind legs and use its tail as a
support. As the Komodo dragon matures, its claws are used primarily as weapons,
as its great size makes climbing impractical.
For shelter, the Komodo dragon digs holes that can measure from 1–3 metres
(3–10 ft) wide with its powerful forelimbs and claws. Because of its large size
and habit of sleeping in these burrows, it is able to conserve body heat
throughout the night and minimize its basking period the morning after.
The Komodo dragon hunts in the afternoon, but stays in the shade during the
hottest part of the day. These special resting places, usually located on ridges
with a cool sea breeze, are marked with droppings and are cleared of vegetation.
They serve as a strategic location from which to ambush deer.
Komodo dragon. Its large, curved claws used in fighting and
eating can be seen
Komodo dragons are carnivores. Although they eat mostly carrion, they will
also ambush live prey with a stealthy approach. When suitable prey arrives near
a dragon's ambush site, it will suddenly charge at the animal and go for the
underside or the throat.
It is able to locate its prey using its keen sense of smell, which can locate
a dead or dying animal from a range of up to 9.5 km (6 miles). Komodo dragons
have been observed knocking down large pigs and deer with their strong tail.
Komodo dragons eat by tearing large chunks of flesh and swallowing them whole
while holding the carcass down with their forelegs. For smaller prey up to the
size of a goat, their loosely articulated jaws, flexible skull, and expandable
stomach allow it to swallow its prey whole.
The vegetable contents of the stomach and intestines are typically avoided.
Copious amounts of red saliva that the Komodo dragons produce help to lubricate
the food, but swallowing is still a long process (15–20 minutes to swallow a
goat). A Komodo dragon may attempt to speed up the process by ramming the
carcass against a tree to force it down its throat, sometimes ramming so
forcefully that the tree is knocked down.
To prevent itself from suffocating while swallowing, it breathes using a
small tube under the tongue that connects to the lungs. After eating up to
80 percent of its body weight in one meal, it drags itself to a sunny location
to speed digestion, as the food could rot and poison the dragon if left
undigested for too long. Because of their slow metabolism, large dragons can
survive on as little as 12 meals a year.
After digestion, the Komodo dragon regurgitates a mass of horns, hair, and
teeth known as the gastric pellet, which is covered in malodorous mucus. After
regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to
get rid of the mucus, suggesting that it, like humans, does not relish the scent
of its own excretions.
The largest animals eat first, while the smaller ones follow a hierarchy. The
largest male asserts his dominance and the smaller males show their submission
by use of body language and rumbling hisses. Dragons of equal size may resort to
"wrestling". Losers usually retreat though they have been known to be killed and
eaten by victors.
The Komodo dragon's diet is wide-ranging, and includes invertebrates, other
reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals,
monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will
eat insects, eggs, geckos, and small mammals.
Occasionally they consume humans and human corpses, digging up bodies from
shallow graves. This habit of raiding graves caused the villagers of Komodo to
move their graves from sandy to clay ground and pile rocks on top of them to
deter the lizards. The Komodo dragon may have evolved to feed on the extinct
dwarf elephant Stegodon that once lived on Flores, according to
evolutionary biologist Jared Diamond.
Because the Komodo dragon does not have a diaphragm, it cannot suck water
when drinking, nor can it lap water with its tongue. Instead, it drinks by
taking a mouthful of water, lifting its head, and letting the water run down its
Auffenberg described the Komodo dragon as having septic pathogens in its
saliva (he described the saliva as "reddish and copious"), specifically the
bacteria: E. coli, Staphylococcus sp., Providencia sp.,
Proteus morgani and P. mirabilis. He noted that while these pathogens
can be found in the mouths of wild Komodo dragons, they disappear from the
mouths of captive animals, due to a cleaner diet and the use of antibiotics.
This was verified by taking mucous samples from the external gum surface of
the upper jaw of two freshly captured individuals. Saliva samples were analyzed
by researchers at the University of Texas who found 57 different strains of
bacteria growing in the mouths of three wild Komodo dragons including
Pasteurella multocida. The rapid growth of these bacteria was noted by
Fredeking: "Normally it takes about three days for a sample of P. multocida
to cover a petri dish; ours took eight hours.
We were very taken aback by how virulent these strains were". This
study supported the observation that wounds inflicted by the Komodo dragon are
often associated with sepsis and subsequent infections in prey animals. How the
Komodo dragon is unaffected by these virulent bacteria remains a mystery.
In late 2005, researchers at the University of Melbourne speculated that the
perentie (Varanus giganteus), other species of monitor, and agamids may
be somewhat venomous. The team believes that the immediate effects of bites from
these lizards were caused by mild envenomation. Bites on human digits by a lace
monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V.
scalaris) all produced similar effects: rapid swelling, localized disruption
of blood clotting, and shooting pain up to the elbow, with some symptoms lasting
for several hours.
In 2009, the same researchers published further evidence demonstrating that
Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed
the presence of two venom glands in the lower jaw. They extracted one of these
glands from the head of a terminally ill specimen in the Singapore Zoological
Gardens, and found that it secreted a venom containing several different toxic
he known functions of these proteins include inhibition of blood clotting,
lowering of blood pressure, muscle paralysis, and the induction of hypothermia,
leading to shock and loss of consciousness in envenomated prey. As a result of
the discovery, the previous theory that bacteria were responsible for the deaths
of komodo victims was disputed.
Kurt Schwenk, an evolutionary biologist at the University of Connecticut
finds the discovery of these glands intriguing, but considers most of the
evidence for venom in the study to be "meaningless, irrelevant, incorrect or
Even if the lizards have venomlike proteins in their mouths, Schwenk argues,
they may be using them for a different function, and he doubts that venom is
necessary to explain the effect of a Komodo dragon bite, arguing that shock and
blood loss are the primary factors.
Mating occurs between May and August, with the eggs laid in September.
During this period, males fight over females and territory by grappling
with one another upon their hind legs with the loser eventually being pinned to
the ground. These males may vomit or defecate when preparing for the fight. The
winner of the fight will then flick his long tongue at the female to gain
information about her receptivity.
Females are antagonistic and resist with their claws and teeth during the
early phases of courtship. Therefore, the male must fully restrain the female
during coitus to avoid being hurt. Other courtship displays include males
rubbing their chins on the female, hard scratches to the back, and licking.
Copulation occurs when the male inserts one of his hemipenes into the female's
cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior
The female lays her eggs in burrows cut into the side of a hill or in the
abandoned nesting mounds of the Orange-footed Scrubfowl (a moundbuilder or
megapode), with a preference for the abandoned mounds. Clutches contain an
average of 20 eggs which have an incubation period of 7–8 months.
Hatching is an exhausting effort for the neonates, who break out of their
eggshells with an egg tooth that falls off soon after. After cutting out the
hatchlings may lie in their eggshells for hours before starting to dig out of
the nest. They are born quite defenseless, and many are eaten by predators.
Young Komodo dragons spend much of their first few years in trees, where they
are relatively safe from predators, including cannibalistic adults, who make
juvenile dragons 10% of their diet. According to David Attenborough, the habit
of cannibalism may be advantageous in sustaining the large size of adults, as
medium-sized prey on the islands is rare.
When the young must approach a kill, they roll around in fecal matter and
rest in the intestines of eviscerated animals to deter these hungry adults.
Komodo dragons take about three to five years to mature, and may live for up to
the Western world
Komodo dragons were first documented by Europeans in 1910, when rumors of a
"land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch
colonial administration. Widespread notoriety came after 1912, when Peter Ouwens,
the director of the Zoological Museum at Bogor, Java, published a paper on the
topic after receiving a photo and a skin from the lieutenant, as well as two
other specimens from a collector.
Later, the Komodo dragon was the driving factor for an expedition to Komodo
Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens
and 2 live ones, this expedition provided the inspiration for the 1933 movie
King Kong. It was also Burden who coined the common name "Komodo dragon."
Three of his specimens were stuffed and are still on display in the American
Museum of Natural History.
The Dutch, realizing the limited number of individuals in the wild, outlawed
sport hunting and heavily limited the number of individuals taken for scientific
study. Collecting expeditions ground to a halt with the occurrence of World War
II, not resuming until the 1950s and 1960s, when studies examined the Komodo
dragon's feeding behaviour, reproduction, and body temperature. At around this
time, an expedition was planned in which a long-term study of the Komodo dragon
would be undertaken.
This task was given to the Auffenberg family, who stayed on Komodo Island for
11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra
Sastrawan captured and tagged more than 50 Komodo dragons. The research from the
Auffenberg expedition would prove to be enormously influential in raising Komodo
dragons in captivity. Research after the Auffenberg family has shed more light
on the nature of the Komodo dragon, with biologists such as Claudio Ciofi
continuing to study the creatures.
The Komodo dragon is a vulnerable species and is found on the IUCN Red List.
There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their
populations are restricted to the islands of Gili Motang (100), Gili Dasami
(100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there
are concerns that there may presently be only 350 breeding females.
To address these concerns, the Komodo National Park was founded in 1980 to
protect Komodo dragon populations on islands including Komodo, Rinca, and Padar.
Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with
Komodo dragon conservation.
Komodo dragons avoid encounters with humans. Juveniles are very shy and will
flee quickly into a hideout if a human comes closer than about 100 metres
(330 ft). Older animals will also retreat from humans from a shorter distance
away. If cornered, they will react aggressively by gaping their mouth, hissing,
and swinging their tail.
If they are disturbed further, they may start an attack and bite. Although
there are anecdotes of unprovoked Komodo dragons attacking or preying on humans,
most of these reports are either not reputable or caused by defensive bites.
Only a very few cases are truly the result of unprovoked attacks by abnormal
individuals which lost their fear towards humans.
Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to
poaching, tourism, and illegal poaching of the dragons themselves have all
contributed to the vulnerable status of the Komodo dragon. Under Appendix I of
CITES (the Convention on International Trade in Endangered Species), commercial
trade of skins or specimens is illegal.
On Padar, a former population of the Komodo Dragon became extinct, of which
the last individuals were seen in 1975. It is widely assumed that the Komodo
dragon died out on Padar after a strong decline of the populations of large
ungulate prey, for which poaching was most likely responsible.
Komodo dragons have long been great zoo attractions, where their size and
reputation make them popular exhibits. They are, however, rare in zoos because
they are susceptible to infection and parasitic disease if captured from the
wild, and do not readily reproduce. In May 2009, there were 13 European, 2
African, 35 North American, 1 Singaporean, and 2 Australian institutions that
keep Komodo dragons.
The first Komodo dragon was exhibited in 1934 at the Smithsonian National
Zoological Park, but it lived for only two years. More attempts to exhibit
Komodo dragons were made, but the lifespan of these creatures was very short,
averaging five years in the National Zoological Park. Studies done by Walter
Auffenberg, which were documented in his book The Behavioral Ecology of the
Komodo Monitor, eventually allowed for more successful managing and
reproducing of the dragons in captivity.
A variety of different behaviors have been observed from captive specimens.
Most individuals are relatively tame within a short period of time, and are
capable of recognizing individual humans and discriminating between more
Komodo dragons have also been observed to engage in play with a variety of
objects, including shovels, cans, plastic rings, and shoes. This behavior does
not seem to be "food-motivated predatory behavior." Even seemingly
docile dragons may become aggressive unpredictably, especially when the animal's
territory is invaded by someone unfamiliar.
In June 2001, a Komodo dragon seriously injured Phil Bronstein—executive
editor of the San Francisco Chronicle—when he entered its enclosure at
the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten
on his bare foot, as the keeper had told him to take off his white shoes, which
could have potentially excited the Komodo dragon. Although he escaped, he needed
to have several tendons in his foot reattached surgically.
Awaiting your comments