Komodo dragon
The Komodo dragon, also known as the Komodo monitor, is a large reptile of the monitor lizard family Varanidae that is endemic to the Indonesian islands of Komodo, Rinca, Flores, Gili Dasami, and Gili Motang. The largest extant population lives within the Komodo National Park in Eastern Indonesia. It is the largest extant species of lizard, with the males growing to a maximum length of and weighing up to.
As a result of their size, Komodo dragons are apex predators, and dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. Komodo dragons' group behavior in hunting is exceptional in the reptile world. The diet of Komodo dragons mainly consists of Javan rusa, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans.
Mating begins between May and August, and the eggs are laid in September; as many as 20 eggs are deposited at a time in an abandoned megapode nest or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and dwell in trees to avoid predators, such as cannibalistic adults, which young Komodo dragons also try to repel by rolling in feces. They take 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 fearsome reputation make them popular zoo exhibits. In the wild, their range has been reduced by human encroachment and is likely to contract further from the effects of climate change; hence, they are listed as Endangered by the IUCN Red List. They are protected under Indonesian law, and Komodo National Park was founded in 1980 to aid protection efforts.
In the Komodo language, the dragons are called sebae 'twins', due to a traditional belief by the Komodo people that they share the same spiritual mother as the dragons. Meanwhile, the Baar people who speak the Baar dialect of Riung language, call the komodo dragon mbau.
Taxonomy
Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum of Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector.The first two live Komodo dragons to arrive in Europe were exhibited in 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 she demonstrated their behaviour at a scientific meeting of the Zoological Society of London in 1928.
The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and two live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon". Three of his specimens were stuffed and are still on display in the American Museum of Natural History.
The Dutch island administration, realizing the limited number of individuals in the wild, soon outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons.
Research from the Auffenberg expedition proved enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.
Etymology
The Komodo dragon is also sometimes known as the Komodo monitor or the Komodo Island monitor in scientific literature, although these names are uncommon. To the natives of Komodo Island, it is referred to as ora, buaya darat, or biawak raksasa.Evolutionary history
Genetic analysis of mitochondrial DNA shows the Komodo dragon to be the closest relative of the Australian lace monitor, with their common ancestor diverging from a lineage that gave rise to the crocodile monitor of New Guinea. A 2021 study showed that during the late Miocene, the ancestors of Komodo dragons had hybridized with the common ancestor of Australian sand monitors.Fossils from across Queensland demonstrate that the Komodo dragon was once present in Australia, with fossils spanning from the Early Pliocene to the Middle Pleistocene, with the youngest confirmed records of the species in Australia dating to at latest 330,000 years ago. In Australia, it coexisted with the even larger monitor species Varanus priscus also known as megalania, the largest terrestrial lizard ever. The oldest records of the Komodo dragon on Flores date to around 1.4 million years ago, during the Early Pleistocene. Additionally, Pleistocene fossils of Varanus found in Java and Timor may belong to the Komodo dragon.
Description
In the wild, adult Komodo dragons usually weigh around, although captive specimens often weigh more. According to Guinness World Records, an average adult male will weigh and measure, while an average female will weigh and measure. The largest verified specimen in captivity was long and weighed, including its undigested food. The largest wild specimen had a length, a snout-vent length and a mass of excluding stomach contents. The heaviest reached a mass of. The study noted that weights greater than were possible but only after the animal had consumed a large meal.The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to in length. Its saliva is frequently blood-tinged because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. The only areas lacking osteoderms on the head of the adult Komodo dragon are around the eyes, nostrils, mouth margins, and parietal eye, a light-sensing organ on the top of the head. Where lizards typically have one or two varying patterns or shapes of osteoderms, komodos have four: rosette, platy, dendritic, and vermiform. This rugged hide makes Komodo dragon skin a poor source of leather. Additionally, these osteoderms become more extensive and variable in shape as the Komodo dragon ages, ossifying more extensively as the lizard grows. These osteoderms are absent in hatchlings and juveniles, indicating that the natural armor develops as a product of age and competition between adults for protection in intraspecific combat over food and mates.
Morphology
Dentition
Komodo dragons have ziphodont teeth, which are defined as teeth that are laterally flattened, recurved, and with serrated tooth crowns where the serrations have a dentine core and a very thin enamel outer layer. This is the same type of dentition observed in many extinct theropod dinosaurs. The teeth of the insectivorous juveniles in contrast are barely recurved, with fewer and less well-developed serrations that lack dentine cores.A 2024 study published in Nature Ecology & Evolution found that Komodo dragons have orange, iron-enriched coatings on their tooth serrations and tips, as an adaptation for maintaining the sharp cutting edges. This feature is also observed to a lesser degree in a few other Australasian to Asian monitor species, though notably absent in a few other species from that range.
Teeth are quickly replaced every 40 days, while maintaining up to 5 replacement teeth for each tooth position at any given time. This high rate of replacement and large number of replacement teeth is similar to that of the crocodile monitor. Many other monitor species as well as Chinese crocodile lizards and beaded lizards only have 1-2 replacement teeth behind each tooth position.
Senses
As with other varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. They were formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoo employee Joan Procter trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.The Komodo dragon can see objects as far away as, but because its retinas only contain cones, it is thought to have poor night vision. It can distinguish colours, but has poor visual discrimination of stationary objects.
As with many other reptiles, the Komodo dragon primarily relies on its tongue to detect, taste, and smell stimuli, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from away. Their tongue-flicking behavior is similar to that of snakes. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.