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THE
KOMODO DRAGONS
"
VARANUS KOMODOENSIS
“The Komodo
dragon ", as befits any creature evoking a mythological beast,
has
many names. It is also the
Komodo monitor, being a
member of the monitor lizard family, Varanidae, which today has one genus, Varanus. Residents of
the island of Komodo call it the ora. Among some on Komodo
and the islands of Rinca and Flores, it is buaya darat (land
crocodile), a name that is descriptive but inaccurate;
monitors are not crocodilians. Others call it biawak raksasa
(giant monitor), which is quite correct; it ranks as the
largest of the monitor lizards, a necessary logical
consequence of its standing as the largest lizard of any
kind now living on the earth…. Within the scientific
community, the dragon is Varanus komodoensis. And most
everyone calls it simply " the Komodo.”
The Komodo
dragon is an ancient species whose ancestors date back over
100 million years. The varanid genus originated between 25
and 40 million years ago in Asia. The Komodo descended from
this species and evolved to its present form over four
million years ago.
The Komodo
is long lived (as are most of the larger reptilian species)
with an
estimated
life expectancy of over 50 years in the wild. In keeping
with its longevity, the Komodo matures late in life,
becoming sexually viable at five to seven years, and
achieving maximum body density in fifteen years. Komodos
are sexually dimorphous, which means males are bigger than
females. The largest recorded specimen was 3.13 meters in
length and was undoubtedly a male. Females rarely exceed 2.5
meters in length. What is perhaps more important, is that
the characteristic bulk is achieved by older dominant males
in clearly delineated territorial areas. As an adult Komodo
can consume up to 80% of its body weight in one gorging,
weight is a highly variable factor, and is largely dependent
on the most recent feeding. A typical weight for an adult
Komodo in the wild is 70 kilograms.
Komodo
dragons are first and foremost opportunistic carnivores, and
predators
second.
Although the Komodo can sprint briefly at 20 kilometers an
hour, it does not chase down game as do the larger mammalian
predators. The Komodo is a stealth predator, which lies
motionless and camoflouged alongside game trails for the
unwary, which tend to be the very young, the old and the
infirm. In an attack, the Komodo lunges at its victim with
blinding speed and clasps it with the serrated teeth of the
jaw. Prey are rarely downed in the initial attack unless the
neck is broken or caratoid artery severed. The more likely
outcome is escape, followed by death a few hours or days
later from septicemia introduced by the virulent strains of
bacteria found in the saliva of the Komodo dragon (the
Komodo survive primarily on carrion and ingest the bacteria
when feeding).
The
Komodo has two highly developed sensory organs – the olefactory and the Jacobson’s - which allow the dragon to
detect rotting carcasses from distances as great as 10
kilometers. The yellow forked tongue is
constantly
being flicked in and out of the mouth, “tasting the air”,
and inserted into the Jacobson’s organ located in the roof
of the mouth. The individual tips are highly sensitive and
are capable of discriminating odors in the magnitude of
millionths of a part. Using the information garnered, the
dragon wends in a seemingly random, winding path which
becomes straighter the closer it approaches to the carrion.
The Komodo is typically a communal feeder and any number of
dragons might arrive at the site of the carcass.
Socialization occurs during feeding at carrion sites, as
does mating. The abdomen
is
slashed first and the intestines and stomach contents
scattered. Young juveniles roll in the fecal matter to mask
their scent from aggressive adults, which attack and
sometimes kill juveniles during feeding. The dominant male
feeds until sated, followed by other dragons in order of
size. While the dominant male is gulping down hindquarters
and ribcages, the braver dragons chance foraging a few
scraps. Virtually the entire carcass is consumed in the
process– head, fur, hooves and bones. After feeding, the
Komodo become quiescent and approachable while their
digestive tracts are converting the food into fat energy
stored in the tail.
Between the
months of May and August, mating occurs at and around
feeding
sites.
As males outnumber females in a ratio of nearly four to one,
the dominant male must fend off other suitors before mating.
Males will engage in slashing, biting and bipedular rearing
onto the tail, until the dominant male is acknowledged by
displays of subservience and the vanquished flees. The
female is forced into a prone position while the male tongue
flicks her body, and in particular, the fold between the
torso and the rear leg close to the cloaca. With Komodo,
the male hemipenes are located here as are the female
genetalia. Once prone, the male mounts onto the back of the
female and inserts one of the two hemipenes into her cloaca
, depending on which side he is perched. The month of
September is when a clutch of 15-30 eggs is buried in a nest
dug with the powerful claws of the female dragon. A typical
nesting site is in the composting vegetative mounds of the maleo birds which are indigenous to
Komodo.
The
gestation period for the eggs is eight to nine months.
Hatchlings, which
average
40 centimeters in length and weigh 100 grams, emerge from
the nest in April and immediately scramble up the nearest
tree to avoid being eaten by the adults. There are plenty
of small lizards, insects and mammals in the canopy after
the brief rainy season in January and February to sustain
the juveniles until they descend to the forest floor roughly
a year later. This period of change between an arboreal and
a terrestial habitat, when the juveniles are a meter in
length, is a time fraught with danger. The juvenile Komodo
is just too bulky to safely ascend many trees, and not big
enough to outrun a ravenous and determined adult.
Cannibalism is a fact of life for this species, and perhaps
is an evolutionary response to the harsh, arid climate of Komodo.
Prey
species for the dragon on Komodo island include deer, boar,
wild buffalo, the maleo bird, snakes, reptiles and small
mammals. On Rinca, the monkeys and wild horses found there
are also constitute prey, as do the goats raised by the
local people. On the odd occasion people are also attacked
by the Komodo dragon. There have been eight recorded
instances of attacks on humans since Komodo has become a
national park, almost all of which occurred on Rinca. |
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