Komodo Dragon (Varanus komodoensis)
Habitat
Komodo
dragons inhabit hot, seasonally arid grasslands, savannas and monsoon forests.
They live mostly in the lowlands, but have occasionally been found at elevations
up to 1,967 feet (600 m).
Physical
Characteristics
Male length: Commonly up to 9 feet (2.75 m) long, including tail, although the
record is slightly over 10 feet (3 m).
Males and
females do not appear to be strikingly different, with the exception
of size. A different arrangement of the scales around the genital opening
is one distinguishing characteristic between the sexes. Adult Komodos
are mostly black, green or gray, with patches of yellow-brown or white.
Weight
Male weight: An exceptionally large male can weigh as much as 550 pounds (250
kg) after a large meal (about half that on an empty stomach).
Females
tend to be shorter and weigh less: up to 7.5 feet (2.3 m) long, and
up to 150 pounds (67.5 kg).
Life
Span
Life span in the wild is unknown. Komodo dragons have lived up to 25 years in
captivity; this is based on estimated age at acquisition.
Diet
In the wild: The primary prey for wild adult dragons
is the Sunda deer, but they also eat birds, snakes, fish, crabs,
snails, small mammals, pigs, water buffalo, eggs, wild horses and
younger Komodos. Komodo dragons are also scavengers, and will eat
almost any type of carrion.
At
the zoo: Mainly rodents, NOT offered alive.
Reproduction
Sexual maturity likely occurs at 5 to 7 years of age. The breeding
season is from May to August, as dominant males fight other males
to gain mating rights with females. Before mating, the winning
male courts the female. To initiate mating, they touch tongues,
rub snouts and scrape chins. When the female accepts his advances
or is too tired to outrun the male, he climbs on her back, scratching
her and sometimes lightly biting her neck. Copulation is a relatively
quick affair. Six to eight weeks
later, in the months of July through September, Komodo females
lay their clutch of 15-30 eggs. The female usually lays them in
a burrow dug into a hillside or in the sand. Eggs are oval, smooth,
and 2 inches (5 cm) wide by 4 inches (10 cm) long. Females rarely
guard the nests and, if so, only for a short amount of time. The
eggs incubate for eight to nine months, and hatch at the beginning
of the dry season in April. The hatchlings are 10-22 inches (25-56
cm) in length, weighing less than 3.5 ounces (100 g).
Life Cycle
Hatchlings are multicolored, with different parts of their body in brown,
yellow, orange and red, covered by a pattern of black and white speckles,
stripes and bands. This coloration camouflages them in trees. Young dragons
remain arboreal for a few years, eating bird eggs, insects and small
mammals. As they grow larger, juveniles eat rats, mice or birds. When
they reach about 4 feet (1.2 m) in length (at 4 to 5 years of age), adolescents
become too large to climb trees, and shift to a terrestrial lifestyle.
Komodos are solitary, but will gather
in groups to rapidly consume large prey, or to breed. Younger dragons
sometime circle a group of feeding adults waiting for a chance at
some leftover food. They do so cautiously, as they can easily be
mauled to death by the dominant male. Smaller dragons are forced
to roam over large areas in search of food and potential mates, sharing
their space with other subordinate lizards. Dominant males are more
aggressive about guarding their territories, which overlap the home
ranges of adult females. Smaller or weaker Komodos use an appeasement
posture to signal the end of a dispute over territory, prey or mates.
Signs of Komodo aggression include puffing out the throat, hissing,
adopting a semicircular stance and thrashing of the tail.
Komodo
dragons bask in the morning sun to raise their body temperature.
During the hottest parts of the day, they retreat to cool areas,
as the outside temperature can easily exceed 100°F (38°C).
At night, to minimize heat loss, they seek cover in brush, caves,
or burrows (either ones made by other animals, or ones they make
themselves).
Massive Monitors
By weight, Komodos are the world's largest lizard; their long, thick tails are
sometimes half their total body length. A hardy constitution has enabled them
to survive for millions of years as the dominant predator in an environment that
is inhospitable to other large meat-eaters. Komodos are also excellent swimmers,
allowing them to travel between islands in search of food or mates. While swimming
they use their tails for propulsion in the strong marine currents.
Komodos have flat, long heads with rounded snouts.
They amble about on short, powerful legs. Small, smooth scales cover their
body. They have powerful claws, and are surprisingly quick in their attack.
For large prey, dragons may attack the prey's feet and lower legs, inflicting
terrible bites in an attempt to bring down the animal. They have been recorded
taking down a 1,300 pound (590 kg) water buffalo. Smaller prey usually get
snapped up with a quick lunge, led with wide open jaws. Despite their fearsome
reputation, Komodos are rarely successful when attacking. For this reason,
carrion sometimes makes up the bulk of their diet.
A Komodo dragon regulates its internal body temperature
by alternately basking in or seeking refuge from the sun. This allows them
to use 10% of the energy a similar-sized mammal would need to survive. Like
most reptiles, Komodos have a low resting metabolic rate. Studies show that
even a large individual can survive on as little as 1 pound (.45 kg) of food
per day. Komodos have an excellent sense of smell. Using a long, yellow forked
tongue, they are able to find carrion up to 6.8 miles (11 km) away. They
also use their tongue to investigate other Komodo defecation sites; it provides
information about another's sex, size and age. Although their eyes detect
motion better than stationary objects, dragons can see objects more than
984 feet (300 m) away. Komodos are not deaf, but they do hear only in a restricted
hearing range of 400-2,000 Hertz.
Terrible Teeth
Komodo dragons have mouths full of flat, serrated teeth, highly adapted for cutting
flesh. The teeth break off easily and are replaced frequently; a dragon may grow
as many as 200 new teeth each year.
A dragon rushes from the vegetation in which it
was camouflaged and ambushes its prey. Its acute sense of smell leads the
Komodo to the dying victim, which has run off some distance. Bacteria in
a Komodo's saliva are highly dangerous, and quickly cause infections. Komodos
are not affected by the infectious saliva of nonlethal bites from other members
of their species. Their saliva is a source of great interest for many scientists,
since its properties may help control diseases in the future.
Komodos actively hunt their prey, roaming their
territory in search of food. They can eat up to 80% of their body weight
at one meal, at a rate of up to 5.5 pounds (2.5 kg) per minute, using their
sharp teeth to carve out huge chunks of flesh and tissue. They may not need
to eat again for weeks. To help them eat so much so quickly, their jaws stretch
wide open, and they produce a large amount of saliva to help move food down
the throat. Komodos are efficient eaters, consuming almost 90% of their prey.
Komodo dragons digest all parts of a meal except for the hair, horns or hooves;
these simply pass through the lizards' digestive tracts. Komodos can extract
up to 80% of their water needs from the flesh of prey. This is especially
helpful in times of drought, which can last for months.
Location at
the Zoo
Woodland
Park Zoo's Komodo dragons
can be viewed in their exhibit at the Trail of Adaptations. Their
exhibit provides a multilevel, naturalistic setting that contains
major components of their normal habitat. Other species of lizards
at Woodland Park Zoo can be found in the Day Exhibit.
Conservation
Connection
Komodo dragons were first listed on Appendix I of
CITES on July 1, 1975 and listed as an endangered species on June
14, 1976. This was due to its limited range and the small number
of wild specimens. Currently, scientists estimate there are 3,000
- 6,000 individuals in the wild, with another 200 in captivity. Komodo
dragons have the smallest range of all the large carnivores.
The government
of Indonesia protects most of the Komodo's range in Komodo National
Park (KNP). KNP, created in 1980, consists of 669 square miles (173,300
sq hec) of land and marine area. Unfortunately, not all Komodos live
in KNP, and there is little protection outside the park. Exportation
of Komodos is allowed only by the president of Indonesia, and they
have been designated the National Animal of Indonesia.
There are several
threats to the Komodo, most of them caused by humans. Habitat loss,
fear (which leads to dragon poaching or poisoning of carrion), pests
and exotic species (such as wild dogs and rats), fire, and expanding
human population all pose problems. Poachers often kill the food
that Komodos rely on, reducing the available prey populations. Komodos
sometimes also eat native livestock, which leads to confrontations
with humans. One uncontrollable threat comes in the form of potential
natural catastrophes. Earthquakes, volcanic eruptions, and tidal
waves occur in the area.
All monitor lizards are listed as Appendix
II (threatened) animals by Convention on International Trade in Endangered
Species (CITES). At least three species of monitors are also protected
under the Endangered Species Act, and listed on Appendix I. Many
species of snakes and lizards are considered endangered or threatened
by the pet trade, or the animal products trade. The United States
is the world's largest market for wildlife products, much of which
includes illegal trafficking and the black market. Almost 2 million
live reptiles are brought into this country every year, while almost
10 million live reptiles are exported annually.
The first captive
breeding of Komodo dragons in the USA occurred in 1992. There is
an international zoo studbook for Komodo dragons, which records their
various bloodlines in captivity as a tool for genetically managing
the zoo population. In addition to maintaining Komodo National Park,
Indonesia also preserves the Komodo by raising captive-bred dragons
for other zoos. As the dominant predator in their habitat range,
Komodo dragons eliminate weak, sick, or dead animals, maintaining
the balance of nature. They keep populations of prey species in check;
otherwise these species could quickly overpopulate and destroy isolated
and fragile island habitats. Though their name may invoke fear, Komodo
dragons rarely attack humans. There are less than 20 credible accounts
of dragon-caused deaths in the past 100 years.
How You Can Help!
The effort to save endangered species requires cooperation and support
at the international, national, regional and individual levels.
You can help in this cause. Join and become active in Woodland
Park Zoo and other conservation organizations of your choice. Please
do not buy products made from wild animal parts. Contact your elected
representatives and express your views about conservation of endangered
species and wild habitats.If you wish to own or keep a reptile
as a pet, contact a local herpetological society, or the American
Federation of Herpetoculture: AFH, P.O. Box 300067, Escondido,
CA, 92030-0067.
Reptiles as Pets
We do not recommend reptiles as pets for most people as they require very specialized diets and environments. We also receive hundreds of requests each year to take former pet iguanas, boas and other reptiles but we cannot accept these due to space, health and unknown backgrounds. If you need to find a reptile or amphibian a new home, we suggest you contact a local herpetological group in your area. In the Puget Sound region, you may contact the Pacific Northwest Herpetological Society as a resource.
Contact Woodland Park Zoo at webkeeper@zoo.org to find out how you can support conservation programs
at the zoo. Learn other ways you can help conserve wildlife and
the habitats they require for survival by visiting our How You Can Help page.
Sources and Suggested Reading
Auffenberg, Walter. The Behavioral Ecology of the Komodo Monitor.University
of Florida, Gainesville, FL. 406 p.Lutz, Dick and J. Marie. 1997. Komodo,
the Living Dragon. Dimi Press, Salem, OR. 173 p.