Komodo dragons, the largest known lizard today, weigh in at anywhere from 50 kg to 125 kg and measuring up to 3 metres in length. Not usually a rain forest species, they are restricted mostly to the open, semi-arid, hot coastal Savannah on the southern Indonesian islands of Komodo, Padar, Rintja and Flores, a chain of islands separating the Flores Sea from the Indian Ocean.
In 1910, a Dutch colonial Lieutenant Van Hensbroek, sent a photograph and skin to the Zoological Museum and Botanical Gardens at Bogor, Java. Director Peter Ouwens realised it was a monitor lizard and published a paper introducing the Komodo to the rest of the world in the 1912, he suggested naming the creature V. komodoensis.
Komodos are prehistoric having existed since the Jurassic period. Komodo Dragon is the common name for, Varanus Komodoensis, from the monitor family, Varanidae. Komodos and dinosaurs share common ancestry belonging to the subclass Diapsida, or "two-arched reptiles," characterised by two openings in the temporal region of the skull. Their earliest fossils date back 300 million years to the Carboniferous period. During the Cretaceous, 100 million years ago, species related to modern varanids appeared in central Asia. During the Eocene, 50 million years ago, terrestrial forms up to three meters in length, preyed on smaller animals and probably raided dinosaur nests. They dispersed throughout Europe, South Asia and even into North America.
There may be as many as 5,000 of these monitor lizards living today. To protect the dragon, the Indonesian government has designated the islands of Padar and Rintja as nature reserves for both the lizard and its prey. Commercial trade in specimens or skins is illegal under the Convention on International Trade in Endangered Species.
Komodo dragons have smooth scales which are brownish grey in colour, they are heavily built with a flattened, triangular head and short powerful legs that terminate in sharp talon clawed feet.These reptiles are swift runners, able to run briefly at speeds up to 20 kilometres per hour. They are climbers and can also swim. Komodo dragons are meat eaters,their hunting strategy is based on stealth and power, spending hours in a single spot awaiting prey. Lethal predators with sharp, saw like teeth, they have a veracious appetite for rodents, monkeys, goats, wild boar and even water buffalo. Their favourite food is deer.
Komodo's teeth are their most dangerous weapon, one bite is enough to kill its prey. The teeth are large, curved and serrated and tear the flesh of their prey. Serrations in the teeth harbour bits of residue meat protein which decompose into about 50 different bacterial strains, some of which are highly septic, in the saliva and so virulent that wounds usually cause fatal infections. Wounds often do not heal, leaving the victim to die within a few days.
The Komodo's jaws muscles and throat enable them to swallow huge chunks of meat incredibly quickly. The movable intramandibular hinge joint opens the lower jaw incredibly wide and their stomachs expand easily, enabling adults to consume up to 80 percent of their own body weight in a single meal. They will eat bones, hooves or swaths of hide. They also eat intestines, but only after violently swinging them to scatter the contents, thus removing faeces from the meal. Because large Komodos cannibalise their young, the smaller ones will roll in fecal material to acquire a scent that their bigger brethren are programmed to avoid consuming.
Monitors vision plays a role in hunting, they can see up to 300 meters away, their eyes pick up movement more effectively than discerning stationary objects. Their retinas possess only cones, they may be able to distinguish colour, but have poor vision in dim light. The Komodo's hearing is restricted to a narrow range of between 400 and 2,000 hertz, as compared to human hearing which detects frequencies of between 20 and 20,000 hertz.The animal is insentient low-pitched voices or high-pitched screams.
Komodo's sense of smell is their primary detector of prey. Their long forked bright yellow tongue darting in and out of its mouth could be mistaken for a flame, as it samples air and retreats to the roof of the mouth, the tongue's two tips make contact with the Jacobson's organs. These chemical analysers recognise airborne molecules, if there is a higher concentration present on the left tongue tip, than that sampled from the right, it tells the Komodo that the prey is approaching from the left. This system, accompanied by a swaggering walk in which the head swings from side to side, enables the dragon sense the existence and direction of prey from as far away as four kilometres, depending on wind conditions.
Komodo dragons dig small caves and spend most nights inside. Mating usually occurs between May and August. Dominant males become embroiled in ritual combat in their quest for females. Their long tails are thick at the base, tapering gradually toward the tip and can deliver a crushing blow to an opponent. They use their tails for support to wrestle in upright postures, grabbing with their forelegs, they attempt to throw their opponent to the ground. Blood is usually drawn, the loser either runs or remains prone and motionless. The victor initiates courtship by flicking his tongue on a female's snout and then over her body.
After mating, the female Komodo will lay between 20 and 40 eggs in September. A delay in laying not only avoids the hot dry season, but gives unfertilised eggs a second chance with subsequent matings. The female lays in depressions dug on slopes or within the pilfered nests of Megapode birds which make heaps of earth mixed with twigs which can reach a meter in height and three meters across. While the eggs are incubating, a period lasting 8 months, females may lie on the nests, protecting their future offspring. No evidence exists, for parental care of newly hatched Komodos.
Hatchlings weigh less than 100 grams and average only 40 centimetres in length. They often fall victim to predators, including their fellow Komodos. Feeding on a diet of insects, small lizards, snakes and birds, they are lucky to survive their first five years, by which time, they can weigh 25 kilograms and stretch two meters long. Slow growth continues throughout their lives, which can span more than 30 years.
Komodos on Flores face the twin threats of prey depletion and habitat encroachment by humans. New settlers slash and burn the monsoon forest and Komodo dragons are among the first species to disappear. The Komodo depends on numerous species of fauna and flora and measures to protect this giant lizard must take into account the entire natural habitat. Attracting over 18,000 visitors a year, the Komodo offers an economically viable option for a protection plan based on ecotourism.
