The Komodo dragon ( Varanus komodoensis ), also known as Komodo monitors , is a species of lizard found on the Indonesian islands of Komodo, Rinca, Flores , Gili Motang, and Padar. A member of the Varanidae monitor lizard family, the largest lizard species, grows up to a maximum length of 3 meters (10 feet) in rare cases and weighs about 70 kilograms (150 pounds).
Their enormous size has been attributed to island gigantism, as no other carnivorous animals fill the niche on the islands where they live. However, recent research has shown that the large size of the Komodo dragon may be better understood as representative of the vast majority of varanid lizard relics who once lived throughout Indonesia and Australia, most, along with other megafauna, died after the Pleistocene (possibly as a result of human activity). The fossils are very similar to V. komodoensis have been found in Australia over 3.8 million years ago, and their size remains stable in Flores, one of the few islands of Indonesia where it is currently found, over the past 900,000 years, "a time marked by the turn of the major fauna, the extinction of the island megafauna, and the arrival of an early hominid of 880 ka [kiloannums]."
As a result of their size, these lizards dominate the ecosystems in which they live. Komodo hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw that secrete some toxic proteins. The biological significance of this protein is debatable, but the gland has been shown to excrete anticoagulants. Komodo dragons' behavior in hunting is amazing in the reptile world. The main Komodo dragons consist mainly of Timor deer, although they also eat a lot of carcasses. Komodo also occasionally attack humans.
The marriage begins between May and August, and the eggs are laid in September. Approximately 20 eggs are stored in abandoned megapode nests or in self-excavated nest holes. The eggs are incubated for seven to eight months, hatched in April, when most insects. Young Komodos are very vulnerable and therefore live in trees, safe from predators and cannibal adults. They need 8 to 9 years to mature, and are estimated to live up to 30 years.
Komodo dragons were first recorded by Western scientists in 1910. Their large size and frightening reputation make them popular zoo exhibits. In the wild, their reach has been contracted for human activities, and they are listed as vulnerable by IUCN. They are protected by Indonesian law, and the national park, Komodo National Park, was established to assist the protection effort.
Video Komodo dragon
Riwayat taksonomi
Komodo dragons were first documented by Europeans in 1910, when rumors about "crocodile lands" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial government. The widespread fame came after 1912, when Peter Ouwens, director of the Zoology Museum in Bogor, Java, published a paper on this topic after receiving photographs and skins from lieutenants, as well as two other specimens from a collector. The first two living Komodo dragons arriving in Europe were exhibited at the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and he demonstrated the behavior of one of these animals at the Scientific Meeting of Zoological Society of London in 1928. Komodo was the driving factor for the expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 living ones, this expedition inspired the 1933 film King Kong . It's also the Burden that creates the common name "Dragon Komodo." The three specimens are filled and still on display at the American Museum of Natural History.
The Netherlands, aware of the limited number of individuals in the banned wildlife hunt and the very limited number of individuals taken for scientific study. Collecting expeditions halted by the onset of World War II, was not continued until the 1950s and 1960s, when the study examined Komodo Dragon's eating, reproductive, and body temperatures. At around this time, an expedition is planned in which long-term study of Komodo will be performed. This assignment was given to the Auffenberg family, who lived on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Son of Letters captured and marked more than 50 Komodo dragons. The research of the Auffenberg expedition will prove to be very influential in increasing the Komodo dragon in captivity. Subsequent research from the Auffenberg family has explained more about the nature of the Komodo dragon, with biologists like Claudio Ciofi continuing to study the creatures.
Etymology
Komodo is also known as a Komodo monitor or Komodo Island in scientific literature, although this is not very common. For the natives of Komodo Island, these are referred to as not , land crocodiles , or giant lizard (giant monitors).
Evolutionary history
The evolution of the Komodo dragon begins with the genus Varanus , which originated in Asia some 40 million years ago and migrated to Australia, where it evolved into a gigantic form (the greatest of all being the recent extinction > Megalania ), aided by the absence of competent placental carnivoras. About 15 million years ago, a collision between Australia and Southeast Asia enabled these larger varanids to return to what is now the Indonesian archipelago, extending their reach as far east as the island of Timor. Komodo dragons are believed to have been distinguished from the ancestors of Australia 4 million years ago. However, recent fossil evidence from Queensland shows that Komodo actually evolved in Australia before spreading to Indonesia. The dramatic decline of sea level during the last glacial period found a wide expanse of the continental shelf occupied by Komodo, becoming isolated in the current island range as sea level rises thereafter. The extinct species of Pliocene of the same size as modern Komodo dragons, such as Varanus sivalensis , have been found in Eurasia as well, showing that they have fared even in environments such as carnivorous mammals to climate change. and an extinction event that marked the beginning of the Pleistocene.
Maps Komodo dragon
Description
In the wild, adult Komodo dragons typically weigh about 70 kg (150 pounds), although captive specimens often weigh more. According to Guinness World Records, the average adult male will weigh 79 to 91Ã,® kg (174 to 201Ã, lb) and is 2.59 m (8.5Ã, ft), while the average women will weigh 68 to 73 kg (150 to 161 lb) and measure 2.29 m (7.5 ft). The largest wild specimen is verified is 3.13 m (10.3 ft) long and weighs 166 kg (366  £), including undigested food.
The Komodo dragon has a tail along its body, and about 60 frequently replaced teeth, serrated teeth that can measure up to 2.5 cm (1 inch) in length. His saliva is often stained with blood, because his teeth are almost completely covered by gingival tissue that is naturally torn apart during breastfeeding. It also has a long, yellow, and branched tongue. The dragon dragon's skin is reinforced by an armored arm, which contains a small bone called osteoderma that acts as a natural chain-letter. This rough skin makes the Komodo dragon become a bad source of skin.
Sense
Like other varanids, Komodo only has a single ear bone, stapes, to transfer vibrations from the tympanic membrane to the cochlea. This arrangement means they may be limited to sounds in the range of 400 to 2,000 hertz, compared to humans who hear between 20 and 20,000 hertz. Initially considered deaf when a study reported no agitation on wild Komodo dragons in response to whispers, raised sounds, or screams. This is debated when the London Zoological Gardens official, Joan Proctor, trains specimens of prisoners to come out to hear his voice, even when he can not be seen.
The Komodo Dragon can see objects as far as 300 m (980 ft), but since the retina contains only cones, it is considered to have poor night vision. It can distinguish colors, but has poor visual discrimination of immovable objects.
Komodo dragons use their tongues to detect, feel, and smell stimuli, as do many other reptiles, with vomeronasal senses using Jacobson organs, rather than using nostrils. With the help of a good wind and the habit of swinging his head from side to side while walking, a Komodo dragon may detect carcasses as far as 4-9.5 km (2.5-5.9 m). There were only a few taster behind her throat. The scales, some of which are reinforced with bone, have sensory plaques that connect to the nerve to facilitate the sense of touch. Scales around the ears, lips, chin, and soles may have three or more sensory plaques.
Behavior and ecology
Komodo dragons prefer hot and dry places, and usually live in dry grasslands, open grasslands, savannas, and lowland tropical forests. As an ectotherm, it is most active during the day, although it shows some nighttime activity. Komodos are solitary, coming together just to breed and eat. They can run fast in short sprints up to 20 km/h (12 mph), dive up to 4.5 m (15 feet), and climb trees proficiently as young through the use of powerful claws. To capture prey out of reach, Komodo can stand on its hind legs and use its tail as a supporter. As it matures, its claws are used primarily as weapons, because their large size makes the climb impractical.
For shelter, the Komodo Dragon digs a hole that can measure from 1 to 3 m (3.3 to 9.8 feet) wide with strong forelimbs and claws. Due to its large size and sleeping habits in this burrow, it is able to conserve body heat throughout the night and minimize its sunburn in the morning afterwards. Komodo hunts in the afternoon, but remains in the shade during the hottest part of the day. This particular resting place, usually located on the back with a cool sea breeze, is marked with dirt and cleansed from plants. They serve as a strategic location to ambush deer.
Diet
Komodo is a carnivore. Although they have been regarded as eating most carcasses, they will often ambush live prey with a hidden approach. When a suitable prey arrives near the dragon's ambush, suddenly the animal will attack at high speed and go to the bottom or throat. Komodo does not attempt to deliberately let prey escape with fatal wounds, but tries to kill prey directly using a combination of damage and blood loss. They have been recorded as killer pigs in seconds, and the observation of Komodo dragons that track prey for long distances may misinterpret cases of prey who escaped from pre-death attacks due to infection. Komodo dragons have been observed knocking down pigs and deer with their powerful tails. He is able to find carcasses using his keen sense of smell, which can find dead or dying animals from a distance of up to 9.5 km (5.9 mi).
Komodo dragons eat by tearing large pieces of meat and swallow them whole while holding the carcass with their front paws. For smaller prey to the size of a goat, loosely artilized jaws, flexible skulls, and enlarged abdomen allow them to swallow prey as a whole. Vegetable contents of the stomach and intestines are usually avoided. Large amounts of red saliva dragons produce relief to lubricate food, but swallowing is still a long process (15-20 minutes to swallow a goat). A dragons may try to speed up the process by crashing the carcass into a tree to force it to fall into its throat, sometimes crashing by force, the tree collapsed. A small tube under the tongue that connects to the lungs allows it to breathe while swallowing. After eating up to 80% of her weight in one meal, it drags herself to a sunny location to accelerate digestion, since food can rot and poison the dragon if left undigested for too long. Due to their slow metabolism, the great dragon can survive only 12 times a year. After digestion, the Komodo drags out the mass of horns, hair, and teeth known as gastric pellets, which are covered in a foul-smelling mucus. After vomiting the stomach pellets, it rubs his face on the ground or in the bushes to get rid of the mucus, indicating it does not enjoy the scent of its own excretion.
The largest animals eat first, while the smaller ones follow the hierarchy. The biggest man affirms his dominance and the smaller man shows their submission using body language and hissing noise. Dragons of the same size can use "wrestling". Losers usually withdraw, although they have been known to be killed and eaten by the winners. Komodo diets are very diverse, including invertebrates, other reptiles (including small dragons), birds, bird eggs, small mammals, monkeys, wild pigs, goats, deer, horses and buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals, while adults prefer to hunt large mammals. Sometimes, they attack and bite people (see first paragraph of this article). Sometimes they consume a human corpse, digging the body from a shallow grave. The habit of robbing this grave caused the Komodo villagers to move their graves from the sand to the clay and piled stones on it to block the lizard. Komodo dragons may have evolved to feed on the extinct dwarf elephant Stegodon that once lived in Flores, according to evolutionary biologist Jared Diamond.
Komodo dragons drink by sucking water into their mouths through buccal pumping (a process that is also used for breathing), raising his head, and letting water flow down his throat.
Saliva
Although previous research proposed that Komodo dragons contain a variety of highly septic bacteria that would help lower prey, research in 2013 suggested that the bacteria in the mouth of the Komodo dragon are common and similar to those found in other carnivores. They really have excellent oral hygiene. As Bryan Fry said: "After they finish eating, they will spend 10 to 15 minutes licking their lips and rubbing their heads on leaves to clean their mouths... Unlike people have been led to believe, they have no cuts of meat which decay from their food in their teeth, cultivate bacteria. "Komodo dragons also do not wait for prey to die and trace them from a distance, like poisonous snakes; Their observations hunt deer, wild boar and in some cases the buffalo reveals that they killed their prey in less than half an hour, using their teeth to cause shock and trauma.
The observation of dying prey from sepsis will then be explained by the natural instinct of water buffalo, which is not the original islands where Komodo lives, ran into the water after fleeing the attack. Warm water filled with dirt will cause infection. The study used a sample of 16 captive dragons (10 adults and six neonates) from three U.S. zoos.
Antibacterial immune factor
Researchers have isolated strong antibacterial peptides from Komodo dragon plasma, VK25. Based on their analysis of these peptides, they have synthesized a short peptide nicknamed DRGN-1 and tested it against many resistant pathogens (MDRs). Preliminary results from these tests indicate that DRGN-1 is effective in killing strains of drug-resistant bacteria and even some fungi. This has the observed additional benefit of significantly promoting wound healing in both uninfected infected wounds and biofilm blends.
Venom
In late 2005, researchers at the University of Melbourne speculated perentie ( Varanus giganteus ), other species of monitors, and agamids might be somewhat venomous. The team believes the direct effects of bites from these lizards are caused by mild envenomation. The bite of the human digits by the lace monitor ( V. Varius ), a Komodo dragon, and monitor the spotted tree ( V. Scalaris ) all produce the same effect: swelling rapidly, localized blood, and shooting pain to the elbow, with some symptoms lasting for several hours.
In 2009, the same researchers published further evidence suggesting Komodo has a venomous bite. MRI scans of the preserved skull indicate the presence of two glands in the lower jaw. The researchers took one of these glands from the severely ill dragon head at the Singapore Zoological Gardens, and found it secreted several different toxic proteins. Known functions of this protein include inhibition of blood clotting, lowering blood pressure, muscle paralysis, and hypothermia induction, which causes shock and loss of consciousness in submerged prey. As a result of that discovery, previous theories that the bacteria responsible for the deaths of Komodo dragons are debated.
Other scientists have argued that these toxic glands 'suspicions have had the effect of underestimating the complex roles played by oral secretions in reptile biology, resulting in a very narrow view of the secret of the mouth and resulting in misinterpretations of reptile evolution'. According to these scientists "oral secretions of reptiles contribute to many biological roles in addition to quickly sending prey". The researchers concluded that, "Calling all in this venomous clade implies a totally non-existent potential danger, misleading in the assessment of medical risks, and confusing the biological assessment of the squamate biochemical system". Evolutionary biologist Schwenk says that even if lizards have proteins like toxins in their mouths, they may use them for different functions, and he doubts the poison is needed to explain the effects of Komodo bites, arguing that shock and blood loss are the main factors.
Reproduction
Mating occurs between May and August, with eggs laid in September. During this period, men fight over women and territories by wrestling with each other on their hind legs, with losers finally wedged to the ground. This man can vomit or defecate while preparing for the fight. The winner of the fight will then flick his long tongue at the female to get information about his acceptance. Women are antagonists and fight with their claws and teeth during the early phase of courtship. Therefore, men should fully hold women during intercourse so as not to be hurt. Other dating shows include men rubbing their chins on women, scratching hard back, and licking. Copulation occurs when a man inserts one hemipena into a female cloaca. Komodo dragons may be monogamous and form a "couple bond", a rare behavior for lizards.
Komodo females lay eggs from August to September and can use some kind of locality; in one study, 60% placed their eggs in orange scrubfowl nests (moundbuilder or megapode), 20% at ground level and 20% in hilly terrain. The females make many nests/camouflage holes to prevent other dragons from eating eggs. The grip contains an average of 20 eggs, which has an incubation period of 7-8 months. Hatching is an exhausting effort for the neonates, who come out of their egg shells with falling egg teeth before long. After cutting themselves off, the hatchlings can lie on their shell for hours before starting digging the nest. They are born very helpless and vulnerable to predation. Sixteen children from one nest averaged 46.5 cm long and weighed 105.1 grams.
Young Komodo dragons spend much of their first few years in the trees, where they are relatively safe from predators, including cannibal adults, because the adolescent dragons produce 10% of their food. Habits of cannibalism may be advantageous in maintaining the large size of adults, because medium-sized prey on the islands is scarce. When the young man did the killing, they rolled around in the stool and rested in the intestines of the exterminating animals to block this hungry adult. Komodo takes about 8 to 9 years to mature, and can live up to 30 years.
Parthenogenesis
A Komodo dragon at the London Zoo named Rivers lay eggs in late 2005 after being separated from the male company for over two years. Scientists initially assumed that he was able to save sperm from his previous encounter with a man, an adaptation known as superfecundation. On December 20, 2006, it was reported that Flora, a Komodo dragon living in the Chester Zoo in England, is the second dragon known to have an uncultivated egg: it puts 11 eggs, and seven of the eggs hatch, all male.. Scientists at Liverpool University in the UK conducted genetic tests on three collapsed eggs after being transferred to an incubator, and verified that Flora had never made physical contact with a male dragon. Once Flora's egg condition has been found, the tests show the River eggs are also produced without outside fertilizing. On January 31, 2008, Sedgwick County Zoo in Wichita, Kansas, became the first zoo in America to document parthenogenesis in Komodo. The zoo has two adult female Komodo dragons, one of them laying eggs as many as 17 eggs on May 19-20, 2007. Only two eggs are incubated and hatch due to space problems; the first hatch on January 31, 2008, while the second hatches on February 1. The two hatchlings were male.
Komodo dragons have a ZW chromosome determination system, which is contrary to the mammalian XY system. The male progeny proves that the infertile Flora egg is haploid (n) and doubles its chromosome then becomes diploid (2n) (with fertilized by a polar body, or by duplication of chromosomes without cell division), rather than by laying diploid eggs by one of the meiotic divisions in his ovaries failed. When a female dragon (with ZW sex chromosomes) reproduces in this way, it gives offspring with only one chromosome from each pair of chromosomes, including only one of its two sex chromosomes. A set of these chromosomes is duplicated in eggs, which develop parthenogenetically. Eggs that receive Z chromosomes become ZZ (male); those who receive the W chromosome become WW and fail to thrive, meaning that only males are produced by parthenogenesis in this species.
It has been hypothesized that this reproductive adaptation allows one female to enter an isolated ecological niche (such as an island) and with parthenogenesis produce male offspring, thereby forming a population of sexual reproduction (through reproduction with offspring that can produce both male and female). young woman). Despite the advantages of such adaptations, zoos are warned that parthenogenesis can damage genetic diversity.
Danger in humans
Attacks on humans are rare, but this species is responsible for some human deaths, both in the wild and in captivity. According to data from Komodo National Park, in 38 years in the period between 1974 and 2012, there were 24 attacks reported to humans, 5 of them deadly. Most of the victims were local villagers living around the park. Report attacks include:
- In 2001, a Komodo dragon attacked Phil Bronstein, an investigative journalist and former husband of actress Sharon Stone, at the Los Angeles Zoo.
- In 2007, a Komodo dragon killed an 8-year-old boy on Komodo Island.
- In 2008, a group of five scuba divers were stranded on the shores of the island of Rinca, and were attacked by dragons. After two days, the ordeal of the diver ended when they were picked up by an Indonesian rescue boat.
- In 2009, Mohammed Anwar, a 31-year-old resident of Komodo Island, was killed by two dragons after he fell from a tree while he was picking apples.
- In 2009, Maen, a national park guide stationed on Rinca Island, was ambushed and bitten by a dragons who walked into his office and lay down under his desk. Despite suffering multiple injuries, the guide was saved.
- In May 2017, Lon Lee Alle, a 50 year old Singaporean tourist, was attacked by a Komodo dragon on Komodo Island. The victim survived the attack, but his left leg was badly injured.
Preservation
Komodo is a vulnerable species and is included in the IUCN Red List. Komodo National Park was established in 1980 to protect the Komodo population on islands including Komodo, Rinca, and Padar. Then, Wae Wuul and Wolo Tado Reserves opened in Flores to help conservation of dragons.
Komodo avoid meeting with humans. Teens are very shy and will soon escape to a hiding place if humans come closer than about 100 meters (330 feet). The older animals will also retreat from humans from a short distance. If cornered, they will react aggressively by gaping their mouths, hissing, and swinging their tails. If they are further disturbed, they can start the attack and bite. Although there are Komodo dragon anecdotes that do not intend to attack or prey on humans, most of these reports have no reputation or are caused by defensive bites. Few cases are actually the result of unwarranted attacks by abnormal individuals, who lose their fear of humans.
Volcanic activity, earthquakes, habitat loss, fires, loss of prey for poaching, tourism, and illegal hunting against dragons themselves all contribute to Komodo's vulnerable status. Under Appendix I of CITES (Convention on International Trade in Endangered Species), commercial trade of leather or specimens is illegal.
By 2013, the total population in the wild is assessed as 3,222 individuals, declining to 3,092 in 2014 and 3,014 by 2015. Populations remain relatively stable on large islands (Komodo and Rinca), but decline in smaller islands such as Nusa Code and Gili Motang, possibly due to reduced availability of prey. In Padar, the previous population of Komodo dragons became extinct, where the last people were seen in 1975. It is widely assumed that Komodo died in Padar after a strong decline of large ungulateous prey populations, whose hunts were likely to be responsible.
In captivity
Komodo has long been a good zoo attraction, where their size and reputation make it a popular exhibit. They are, however, rare in zoos because they are susceptible to infections and parasitic diseases if captured from the wild, and not easily reproduce. As of May 2009, there were 13 Europeans, 2 Africans, 35 North Americans, 1 Singaporeans, and 2 Australian agencies that kept the dragons.
Komodo dragons first shown at the London Zoo in 1927. A dragons displayed in 1934 at the National Zoo in Washington, D.C., but lived for only two years. More effort to showcase Komodo, but the animal's age is very short, averaging five years at National Zoological Park. The study, conducted by Walter Auffenberg, documented in his book The Behavioral Ecology of the Komodo Draw, was eventually allowed to manage and reproduce more successful dragons in captivity.
Various behaviors have been observed from captive specimens. Most individuals are relatively benign in a short time, and are able to recognize individual humans and distinguish between familiar guards. Komodo dragons have also been observed to play with various objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be a "food-motivated predator behavior".
Even dragons that seem benign can become aggressively unpredictable, especially when the animal area is attacked by someone it does not recognize. In June 2001, a dragon Komodo seriously injured Phil Bronstein, who later became the husband of actress Sharon Stone, when she entered the cage at the Los Angeles Zoo after being invited by her goalkeeper. Bronstein was bitten on his bare feet, for the guard told him to remove white shoes and socks, which the guard said had the potential to excite the Komodo because it was the same color as the white mouse in the zoo that fed the dragon. Though he ran away, Bronstein needed to have some tendons on his legs that were reconnected with surgery.
See also
- Papua monitor ( Varanus salvadorii ) - A monitor lizard often confirms to be the longest lizard
- Toxicofera - A hypothetical clade that includes all venomous reptiles, including Komodo dragons
- Varanus priscus (formerly known as Megalania prisca ) - An extinct varanoid lizard from Pleistocene Australia
- Asian water monitor
- Indonesian Komodo Fauna Museum and Reptile Park
References
Further reading
- Attenborough, David (1957). Zoo Quest for a Dragon . London: Lutterworth Press.
- Auffenberg, Walter (1981). Behavioral Ecology from Komodo Dragons . Gainesville: University Presses of Florida. ISBNÃ, 0-8130-0621-X.
- Burden, W. Douglas (1927). Dragon Komodo Dragon: An Expedition to a Lost World from the Dutch East Indies . New York, London: G.P. Putnum's Sons.
- Eberhard, Jo; King, Dennis; Green, Brian; Knight, Frank; Keith Newgrain (1999). Supervisor: Biology of Varanid Lizards . Malabar, Fla: Krieger Publishing Company. ISBNÃ, 1-57524-112-9. Lutz, Richard L; Lutz, Judy Marie (1997). Komodo: The Living Dragon . Salem, Or: DiMI Press. ISBN: 0-931625-27-0. Ã,
Source of the article : Wikipedia
0 Comments