Australia The Origin of Komodo Dragons

“I shouted and he came to help me but he didn’t like to come up because the dragon was still moving around,” Maen explains. “Then he saw the blood on the floor and he got everyone from the kitchen. All the people come running here, but other dragons follow along as well.” ~ quoted from timetravelturtle

Komodo dragons (Varanus komodoensis) are the largest of the monitor lizards, the largest living lizards to date, and the top predators in their habitat due to the size and ferocity. A fully grown komodo dragon can grow up to 3 meters in length and 70 kilograms in weight. A female dragon can lay dozens of eggs without mating, and her size is smaller than that of the male. Fossil record shows that komodo dragons are the last of a group of lizards called varanids.

These lizards are cannibals and they can smell blood kilometers away. They eat their young and sometimes their eggs as well. Young komodo dragons will roll themselves in entrails and faeces to prevent being eaten by mature dragons. Young komodo dragons are also able to climb trees. Their saliva contains over 50 types of bacteria, 7 of them are highly septic, which come in handy when hunting their preys, e.g. birds, rodents, snakes, fish, crabs, snails, and mammals including goats, deer, wild boar, water buffalo, and sometimes even humans. For nearly a million years the lizards have been about the same size. It is indeed a fearsome ancient species.

Komodo dragons have been living on five islands (Komodo, Rinca, Gili Montang, Gili Dasami and Flores) in southern Indonesia as their natural habitat. Komodo dragons are endangered due in part to their limited range. It appears that they have been hunted over the years, but not to the extent of decimating the population. Komodo National Park and strict anti-poaching laws in Indonesia have helped protect the giant lizards. But, how come they can only be found roaming freely on those islands? Where is the origin of komodo dragons?

Komodo dragons were discovered for the first time by Western scientists back in 1910. Under harsh environmental conditions, komodo dragons have been so far known to be able to swim within short range distance between islands—and those five islands are close to each other. But now scientists have also found out that komodo dragons most likely evolved in Australia and dispersed westward to their current habitat in Indonesia.

In the past, scientists suggested that komodo dragons might have developed from a smaller ancestor isolated on the Indonesian islands, evolving into their current size as a response to the lack of competition from other large predators or as specialist hunters of pygmy elephants known as Stegodon. But recently, a team of scientists have unearthed numerous fossils from eastern Australia dated from 300,000 years ago to 4 million years ago that they now know belong to komodo dragons. The fossils and the bones of komodo dragons are identical. They also said that the ancestor of komodo dragons most likely had evolved in Australia and then they spread westward, reaching Flores island about 900,000 years ago. Comparisons between the fossils and the bones of the living komodo dragons show that they have been about the same size since then.

However, one question remains unanswered: Why did komodo dragons go extinct on Australia while surviving on a few isolated Indonesian isles? No matter what the answer is, now we can also mention that Australia is the origin of komodo dragons.

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Via livescience, sandiegozoo, komodonationalpark

Photo: Freeimages.com/Lauren Burbank; herval / Foter / CC BY-NC-SA