Komodo dragon

Komodo dragons are large lizards with long tailsstrong and agile necksand sturdy limbs. Their tongues are yellow and forked. Adults are an almost-uniform stone color with distinctlarge scaleswhile juveniles may display a more vibrant color and pattern.

The muscles of the Komodo's jaws and throat allow it to swallow huge chunks of meat with astonishing rapidity. Several movable jointssuch as the intramandibular hinge opens the lower jaw unusually wide. The stomach expands easilyenabling an adult to consume up to 80 percent of its own body weight in a single mealwhich most likely explains some exaggerated claims for immense weights in captured individuals. When threatenedKomodos 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 femalesno 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. These wild dragons typically weigh about 154 pounds (70 kilograms)but the largest verified specimen reached a length of 10.3 feet (3.13 meters) and weighed 366 pounds (166 kilograms). Males tend to grow larger and bulkier than females.

Komodo dragons are limited to a few Indonesian islands of the Lesser Sunda groupincluding RintjaPadar and Floresand of course the island of Komodothe largest at 22 miles (35 kilometers) long. They have not been seen on the island of Padar since the 1970s.

They live in tropical savanna forests but range widely over the islandsfrom beach to ridge top.

Komodo dragons live about 30 years in the wildbut scientists are still studying this.

Komodo dragons eat almost any kind of meatscavenging for carcasses or stalking animals that range in size from small rodents to large water buffalo. Young feed primarily on small lizards and insectsas well as snakes and birds. If they live to be 5 years oldthey move onto larger preysuch as rodentsmonkeysgoatswild boars and deer (the most popular meal). These reptiles are tertiary predators at the top of their food chain and are also cannibalistic.

Although the Komodo dragon can briefly reach speeds of 10 to 13 mph (16 to 20 kph)its hunting strategy is based on stealth and power. It can spend hours in one spot along a game trail — waiting for a deer or other sizable and nutritious prey to cross its path — before launching an attack.

Most of the monitor's attempts at bringing down prey are unsuccessful. Howeverif it is able to bite its preybacteria and venom in its saliva will kill the prey within a few days. After the animal dieswhich can take up to four daysthe Komodo uses its powerful sense of smell to locate the body. A kill is often shared between many Komodo dragons.

Monitors can see objects as far away as 985 feet (300 meters)so vision does play a role in huntingespecially as their eyes are better at picking up movement than at discerning stationary objects. Their retinas possess only conesso they may be able to distinguish color but have poor vision in dim light. They have a much smaller hearing range than humans andas a resultcannot hear sounds like low-pitched voices or high-pitched screams.

The Komodo dragon's sense of smell is its primary food detector. It uses its longyellowforked tongue to sample the air. It then moves the forked tip of its tongue to the roof of its mouthwhere it makes contact with the Jacobson's organs. These chemical analyzers "smell" preysuch as a deer, by recognizing airborne molecules. If the concentration of molecules present on the left tip of the tongue is greater than that sample from the rightthe Komodo dragon knows that the deer is approaching from the left.

This systemalong with an undulatory walkin which the head swings from side to sidehelps the dragon sense the existence and direction of food. At timesthese reptiles can smell carrionor rotting fleshup to 2.5 miles (4 kilometers) away.

This lizard's largecurved and serrated teeth are its deadliest weapontearing flesh with efficiency. The tooth serrations hold bits of meat from its most recent mealand this protein-rich residue supports large numbers of bacteria. Some 50 different bacterial strainsat least seven of which are highly septichave been found in the saliva. Researchers have also documented a venom gland in the dragon's lower jaw. In addition to the harmful bacteriathe venom prevents the blood from clottingwhich causes massive blood loss and induces shock.

The Komodo's bite may be deadlybut not to another Komodo dragon. Those wounded while sparring with each other appear to be unaffected by the bacteria and venom. Scientists are searching for antibodies in Komodo dragon blood that may be responsible. 

The lizard's throat and neck muscles allow it to rapidly swallow huge chunks of meat. Several movable jointssuch as the intramandibular hingeopen its lower jaw unusually wide. The dragon's stomach also easily expandsenabling an adult to consume up to 80 percent of its own body weight in a single meal. When threatenedKomodo dragons can throw up the contents of their stomachs to lessen their weight in order to flee.

Komodo dragons are efficient eatersleaving behind only about 12 percent of their prey. They eat boneshooves and sections of hideas well as intestines (after swinging them to dislodge their contents).

At the Smithsonian's National Zoothe Komodo dragon eats rodentschicks and rabbits. Occasionallyhe consumes fish and carcass meals of beef.

They escape the heat of the day and seek refuge at night in burrows that are just barely large enough for them.

Because large Komodos cannibalize young onesthe young often roll in fecal materialthereby assuming a scent that the large dragons are programmed to avoid. Young dragons also undergo rituals of appeasementwith 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.

Determining the sex of a Komodo dragon is challenging for researchersas no obvious morphological differences distinguish males from females. One subtle clue is a slight difference in the arrangement of scales just in front of the cloaca. Courtship opportunities arise when groups assemble around carrion to feedand mating occurs between May and August.

Dominant males compete for females in ritual combat. Using their tails for supportthey wrestle in upright posturesgrabbing each other with their forelegs as they attempt to throw the opponent to the ground. Blood is often drawnand the loser either runs away or remains prone and motionless.

Females lay about 30 eggs in depressions dug on hill slopes or within the pilfered nests of megapodes — largechicken-like birds that make nests of heaped earth mixed with twigs that may be as long as 3 feet (1 meter) in height and 10 feet (3 meters) across.

Delays in egg laying may occurwhich could help the clutch avoid the brutally hot months of the dry season. Additionallyunfertilized eggs may have a second chance with subsequent mating. While the eggs incubate in the nest for about nine monthsthe female may lay on the nest to protect the eggs. No evidence of parental care for newly hatched Komodos exists.

The hatchlings weigh less than 3.5 ounces (100 grams) and average 16 inches (40 centimeters) in length. Their early years are precariousand they often fall victim to predatorsincluding other Komodo dragons. At 5 years oldthey weigh about 55 pounds (25 kilograms) and average 6.5 feet (2 meters) long. At this timethey begin to hunt larger prey. They continue to grow slowly throughout their lives.

While they have been hunted (legally and illegally)their population decline is due to their limited range. No Komodo dragons have been seen on the island of Padar since the 1970s, the result of widespread poaching of deerthe reptile's primary source of prey.

Komodo National Parkestablished in 1980and strict anti-poaching laws have helped protect the dragonsalthough illegal activity still takes place. Villagers sometimes poison carrion bait to reduce the populationmuch 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.

Each yearmore than 18,000 people travel to Indonesia to visit sites that still have these animals. The tourism provides an economic incentive for local people to support the Komodo dragon's protection.

The Smithsonian's National Zoo was the first zoo outside of Indonesia to successfully hatch Komodo dragons. 

Zoo visitors can see a young male Komodo dragon named Onyx at the Reptile Discovery Center. A female named Marigold also lives at the Zoo behind the scenes.