Tuesday, July 14, 2009

Komodo dragon


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. 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.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.
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. A typical weight for an adult Komodo in the wild is 70 kilograms.
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. 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 Komodos 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 Komodos, 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.
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