Wednesday, October 3, 2012

KOMODO DRAGONS

Komodo dragons are not real dragons, but they have the word "dragon" in their name, so I think that the Year of the Dragon is a good time to write about them.  Another name for them is Komodo monitor, and their scientific name is Varanus komodoensis.  They are the largest type of lizards still alive today, and they only live in the Indonesian Islands of Komodo, Rinca, Flores, Gili Montang, and Padar.  Komodo dragons can be as big as 10 feet in length and can weigh 150 pounds.  A long, long time ago, like back in the Pleistocene Era, there were lots of giant lizards, but only the Komodo monitor is still around today.









Eating a buffalo. Yum!
Photo by Kevin Flay
The only thing that Komodo dragons like to eat is meat.  Sometimes they hunt their own meat, and other times they eat animals that are already dead.  The way they hunt is that they hide someplace and wait patiently for some nice, tasty animal to walk by.  This could be another reptile, a bird, monkey, boar, goat, deer, horse, or water buffalo.  Then the dragon charges out and bites the prey in the throat or leg.  If it doesn't kill the animal right away, it just follows it by scent until it dies, which it always will because the bite of the Komodo dragon is full of horrible, nasty bacteria that can kill you really fast.





Photo by Kenneth Garrett
Nobody knows how Komodo dragons can have all these bacteria inside them and not get sick themselves, but they don't.  And besides having a bite so full of bacteria, it turns out that Komodo dragons also have two venom glands in their lower jaw.  But the Komodo dragons living in captivity don't have all that toxic bacteria stuff in their mouths, and that's because they eat a cleaner diet and take antibiotics.









Komodo dragon skin
Komodo dragons don't have a very good sense of hearing or sight, but their sense of smell is incredible.  They take in scents by using their forked yellow tongues, and not through their nostrils.  They can smell dead or dying animals from a distance of 6 miles away.  I hate to admit it, but this might be even better than a dog could do.  Anyway, when the big lizards catch up with their meal, they eat by tearing off huge chunks of meat and swallowing them without bothering to chew.  In fact, if a Komodo dragon is eating something the size of a goat or smaller, the lizard will just open its jaws really wide and swallow the animal whole.  This swallowing process might take a while, even though the Komodo has tons of red saliva to help things slide down.  To get a whole goat swallowed could take 15 or 20 minutes.  Sometimes the Komodo dragon will ram the carcass against a tree to help force it down faster.


The way a Komodo dragon keeps breathing while it is swallowing something big is that it uses a little tube under his tongue to get air to its lungs.  After it finishes swallowing its food, which might be up to 80% of its body weight, the dragon waddles off to sit in the sun, because warmth will help make the digestion go faster.  If the food takes too long to digest, it could rot and poison the dragon.  When the good parts have been digested, the lizard regurgitates something called a gastric pellet, which contains a bunch of horns, hair, and teeth, covered with some really stinky mucous.  Komodo dragons have such a slow metabolism that a large dragon can get by on only twelve meals a year.




The favorite kinds of places where these dragons like to live is in dry, open grassland, savannas, and tropic forests at low elevations.  They dig large holes to sleep in, and they are mostly only active during the daytime.  In the very hottest part of the day, they hang out in the shade where there is a nice breeze.  Komodo dragons stay by themselves a lot of the time, unless it's mating season, which is between May and August.







During this time, the males fight over the females by standing on their hind legs and wrestling.  The winner pins the loser on the ground.  After mating, the female dragon lays about 20 eggs in a burrow that she digs in the side of a hill or else in the abandoned nesting mound of an Orange-footed Scrubfowl.  Seven or eight months later, the baby dragons start to think about coming out of their shells.  It's a tough job to get out, and they have to use an egg tooth to cut through the shells.  Sometimes they need to rest up for a few hours before they can then dig out of their nests.



An Indonesian coin
The babies are totally defenseless when they are born, so a lot of them are eaten by predators, including adult Komodo dragons, whose diet is about 10% baby dragons.  If the hatchlings can make it to a tree and climb up in it, they are fairly safe because the adults are too heavy to climb trees.  The young dragons live in the trees until they are about 4 years old and 4 feet long.  They eat eggs, grasshoppers, beetles, and geckos.  They are mature by the time they are 5 years old, and they might live as long as 50 years.










In 1910, Lieutenant van Steyn van Hensbroek, who was part of the Dutch colonial adminstration, was the first European to discover Komodo dragons.  He sent a photo and dragon skin to Peter Ouwens, the director of the Zoological Museum at Bogor, Java, who published a paper on the dragon.  Then in 1926, W. Douglas Burden went on an expedition to Komodo Island to study the lizards.  He returned to the U.S. with 12 preserved specimens and 2 live ones, and he also invented the phrase "Komodo dragon."  It was Mr. Burden's expedition that gave filmmakers the idea for the 1933 movie King Kong.












Here's a map that shows where Komodo dragons live
























Today there are between 3,000 and 5,000 Komodo dragons left in Indonesia.  This population is stable, but it is considered to be ENDANGERED because of the problems of poaching, natural disasters, loss of habitat, and not enough females who are laying eggs.

Personally, I would not ever want to meet up with a Komodo dragon because I would not want to get bitten by a mouthful of sharp teeth and bacteria.  And I especially wouldn't want to be swallowed whole!


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