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Komodo dragon

Class: Reptilia
Order: Squamata
Family: Varanidae
Genus and Species: Varanus komodoensis
  • Very large lizard with dry, gray, rough-looking skin and large claws
  • Lizard resting on the grass with its legs outstretched
  • Resting lizard with its long pinkish, forked tongue visible. There are holes in its head for the ear and nasal cavity.
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Komodo dragon

The largest living lizard in the world, the Komodo dragon is also one of the few venomous lizards. It is native to the island of Komodo as well as a handful of other Indonesian islands. 

Physical Description

A large lizard, Komodo dragons have long tails; strong, agile necks and sturdy limbs. Adult Komodo dragons are an almost-uniform stone color with distinct, large scales. Juvenile dragons may display more vibrant coloring and patterning. Their tongues are yellow and forked, appropriate for their draconian name.

The muscles of the Komodo's jaws and throat allow it to swallow huge chunks of meat with astonishing rapidity. Several movable joints, such as the intramandibular hinge opens the lower jaw unusually wide. The stomach expands easily, enabling an adult to consume up to 80 percent of its own body weight in a single meal, which most likely explains some exaggerated claims for immense weights in captured individuals. When threatened, Komodos can throw up the contents of their stomachs to lessen their weight in order to flee.

Although males tend to grow larger and bulkier than females, no obvious morphological differences mark the sexes. One subtle clue does exist: a slight difference in the arrangement of scales just in front of the cloaca. Sexing Komodos remains a challenge for human researchers; the dragons themselves appear to have little trouble figuring out who is who.


The Komodo dragon is the largest living lizard in the world. The largest verified specimen reached a length of 10.3 feet (3.13 meters) and weighed 366 pounds (166 kilograms). The largest wild dragons more typically weigh about 154 pounds (70 kilograms).

Native Habitat

Komodo dragons are limited to a few Indonesian islands of the Lesser Sunda group including Rintja, Padar and Flores, and of course the island of Komodo. They live in tropical savanna forests, but range widely over the islands, from beach to ridge top.

Food/Eating Habits

Monitors can see objects as far away as 985 feet (300 meters), so vision does play a role in hunting, especially as their eyes are better at picking up movement than at discerning stationary objects. Their retinas possess only cones, so they may be able to distinguish color but have poor vision in dim light. They have a much smaller hearing range than humans. The result is an animal that cannot hear such sounds as a low-pitched voice or a high-pitched scream.

Vision and hearing are useful, but the Komodo's sense of smell is its primary food detector. The Komodo smells much like a snake does. It uses its long, yellow forked tongue to sample the air, after which the two tongue tips retreat to the roof of the mouth where they make contact with the Jacobson's organs. The chemical analyzers "smell" a deer by recognizing airborne molecules. If the concentration present on the left tongue tip is higher than that sampled from the right, the Komodo knows that the deer is approaching from the left. This system, along with an undulatory walk in which the head swings from side-to-side, helps the dragon sense the existence and direction of odoriferous carrion from as far away as 2.5 miles (4 kilometers), when the wind is right.

When the Komodo is hunting and catches its prey, such as a deer, it attacks the feet first, knocking the deer off balance. When dealing with smaller prey, it may lunge straight for the neck. The dragon's basic strategy is simple: try to smash the quarry to the ground and tear it to pieces. Strong muscles driving powerful claws accomplish some of this, but the Komodo's teeth are its most dangerous weapon. They are large, curved and serrated and tear flesh with efficiency. If the deer fails to escape immediately, the Komodo will continue to rip it apart. Once convinced that its prey is incapacitated, the dragon may break off its offensive for a brief rest. The deer is now badly injured and in shock. The dragon then launches the final blow, a belly attack. The deer quickly bleeds to death and the Komodo begins to feed.

Its tooth serrations harbor bits of meat from the Komodo's last meal, either fresh prey or carrion. This protein-rich residue supports large numbers of bacteria. They have found some 50 different bacterial strains, at least seven of which are highly septic, in the saliva. If the prey somehow maneuvers away and escapes death at this point, chances are that its victory, and it, will be short- lived. The infections it incurs from the Komodo bite will probably kill it in less than a week. In addition to the bacteria in their saliva, researchers have recently documented that Komodos do have a venom gland found in their lower jaw. In addition to the damage the bacteria in their saliva do, the venom prevents the blood from clotting.

The Komodo bite is not deadly to another Komodo, however. Dragons wounded in battle with their comrades appear to be unaffected by the otherwise deadly bacteria and venom. Scientists are searching for antibodies in Komodo blood that may be responsible for saving them from the fate of the infected prey.

Large mammalian carnivores, such as lions, tend to leave 25 to 30 percent of their kill unconsumed, declining the intestines, hide, skeleton and hooves. Komodos eat much more efficiently, forsaking only about 12 percent of the prey. They eat bones, hooves and swaths of hide. They also eat intestines, but only after swinging them vigorously to scatter their contents. This behavior removes feces from the meal.

Komodo dragons eat almost any kind of meat. They scavenge from carcasses or stalk animals ranging in size from small rodents to large water buffalo. The young feed on mostly small gecko lizards or insects. They are tertiary predators (predator at the top of the food chain) and are cannibalistic. They can detect carrion from a considerable distance, about 2.5 miles (4 km), and actively seek it out. When hunting, Komodos hunt along game trails, where they wait for deer or boar to pass by. They then attack the prey; most attempts are unsuccessful in bringing down an animal. However, if the dragon is able to bite the prey, toxic bacteria and venom in the saliva will kill the prey within the next few days. After the prey animal dies, which may take up to four days, Komodos use their powerful sense of smell to locate the dead animal. A kill is usually shared by many Komodo dragons and very little is wasted.

The Smithsonian's National Zoo's Komodo dragon eats rodents, chicks and rabbits weekly. Occasionally, he gets fish.

Social Structure

Because large Komodos cannibalize young ones, the young often roll in fecal material, thereby assuming a scent that the large dragons are programmed to avoid. Young dragons also undergo rituals of appeasement, with the smaller lizards pacing around a feeding circle in a stately ritualized walk. Their tail is stuck straight out and they throw their body from side to side with exaggerated convulsions.

Reproduction and Development

Most mating occurs between May and August. With a group assembled around the carrion, the opportunity for courtship arrives. Dominant males can become embroiled in ritual combat in their quest for females. Using their tails for support, they wrestle in upright postures, grabbing each other with their forelegs as they attempt to throw the opponent to the ground. Blood is usually drawn and the loser either runs or remains prone and motionless.

The female Komodo lays about 30 eggs. A delay in laying may serve to help the clutch avoid the brutally hot months of the dry season. In addition, unfertilized eggs may have a second chance with a subsequent mating. The female lays her eggs in depressions dug on hill slopes or within the pilfered nests of megapodes—large, chicken-like birds that make nests of heaped earth mixed with twigs that may reach 3 feet (1 meter) in height and 10 feet (3 meters) across. While the eggs are incubating—about nine months—females may lie on the nests, protecting their future offspring. No evidence exists, however, for parental care of newly hatched Komodos.

The hatchlings weigh less than 3.5 ounces (100 grams) and average 16 inches (40 centimeters) in length. Their early years are precarious, and they often fall victim to predators, including their fellow Komodos. They feed on a diverse diet of insects, small lizards, snakes and birds. Should they live five years, they can weigh 55 pounds (25 kilograms) and stretch 6.5 feet (2 meters) long. By this time, they have moved on to bigger prey such as rodents, monkeys, goats, wild boars and the most popular Komodo food, deer. Slow growth continues throughout their lives, which may last more than 30 years

Sleep Habits

They escape the heat of the day and seek refuge at night in burrows that are just barely bigger than they are.


Dragons live about 30 years in the wild, but scientists are still studying this.

While they have been hunted (legally and illegally), their population decline is due to their limited range.

Komodo National Park, established in 1980, and strict anti-poaching laws have helped protect the dragons, although illegal activity still takes place. Villagers sometimes poison carrion bait to reduce the population, much like ranchers of the American West poison sheep carcasses to rid the area of coyotes and mountain lions. The Dutch colonial government instituted protection plans as early as 1915.