Greatest of the Varanus lizards, the Komodo monster (V. komodoensis.) could have been applied to this in the past. Of all the mythical dragons breathing fire, this is the most realistic. Instead of actual fire, its breath is very smelly and the jaws secrete a venom, so that prey die after a bite has been made. Other lizards of the same genus inhabit Australia, Africa and Asia, telling us basically how old the lineage is.
They don't quite compare with the terrible dragons (that translates as "dino-saur"), but they do try. In the (Cretaceous) past their relatives, the mososaurs, were pretty terrible themselves, at 17m long, while an equally huge monitor from the Pleistocene is an iconic fossil in Australia.
The island, and the neighbouring Rinca, Padar and Flores islands, is the only habitat for the species. Whether they swim to each island regularly or if the other islands have sub-species would be great to know, but so far, no-one has dared come forward to test their DNA! The nearest relatives are something like the water monitors of Asia, but this lizard has been around a long time for a modern reptile. The lizards and snakes developed in the Cretaceous, with mainly snakes taking on the roles of big carnivores. The Komodo is up to 3.1 meters long (11 feet) and has a mass of 166kg (365lb). Not a pleasant sight for a Robinson Crusoe.
Close up of a Komodo Dragon mouth - Komodo image via Shutterstock
While a population of 5000 could suffice for a small island, only 350 of them are breeding females and any natural disaster could wipe out the whole species. However, scientists being curious beats, it has been discovered that these females are parthenogenetic, as several other lizards are. One female in Chester Zoo( UK) has been recently proven to produce viable eggs, with no male for hundreds of miles. They are classed as VU (vulnerable) under the IUCN. Red List.
As the adults will eat virtually anything, the young are arboreal till at least eight months. Adults can climb trees, but are so heavy that young can climb much more easily. The eggs are laid after the hot summer of July and August although there can be two broods a year. Earth and leaves are used by the female to cover the dug-out nest but after hatching, parental interest is lacking, apart from possibly snatching a quick snack. After eight months several zoos have established, that egg hatches into a small dragon, then a lifetime of fifty years is possible, though fraught with menace from its older relatives!
The home range is 1.9 km2, but overlap is allowed as the dominant dragon always eats first. Tunnels are occasionally dug to avoid overheating. Smell is mainly used for hunting. The adults are very popular with tourists (and vice-versa, in the past) so that prey is often delivered to a lazy pack of large males who wait for the daily bus. You may be aware that lizards require much less food than mammals as they don't regulate body temperature, so a little food each would last a long time. If required to kill large or small animals, the hunt simply consists of an ambush followed by a bite or two. The poison and (possibly pathogenic bacteria in the mouth) often kill the prey even if blood loss doesn't weaken it. Like the constricting snakes, this lizard's throat opens wide for large pieces to travel down. No natural predators are known, apart from humans.