Breeding Komodo dragons no simple 'boy meets girl'
It's hard to tell the sexes apart
March 21, 1996
Web posted at: 9:20 a.m. ESTFrom Correspondent Ann Kellan
SAN DIEGO, California (CNN) -- The endangered Komodo dragons are the largest lizards in the world, with the strength to eat a human and a bite that fells their victims like a poison dart. (536K QuickTime movie)
Even though there's an international effort to protect the dragons, named after one of the islands in Indonesia where they're found, successful breeding in captivity is not a simple matter of boy meets girl.
Ora is one of the first Komodo dragons to hatch outside Indonesia and could grow to be 10 feet long and weigh as much as 300 pounds. His saliva is poisonous enough to kill a human; he eats small mammals for lunch.
With 4,000 of his relatives left in the world, the biggest problem with breeding Ora is telling the difference between him and his prospective mate. You can't tell by looking.
"Currently, of the zoos that are housing Komodo dragons worldwide, there are over 50 animals that are between two and four years of age," says Allison Albert, a comparative physiologist at the Center for Reproduction of Endangered Species in San Diego. "As far as I know, the sex has not been determined for any of those at this point."
Dr. Pat Morris, an associate veterinarian with the San Diego Zoo, says you don't know if a dragon is a female until there are eggs in its cage.
Researchers at the Center for Reproduction of Endangered Species are studying two ways of determining a Komodo dragon's sex: ultrasound and a blood test.
According to researchers, ultrasound is a fairly simple and painless procedure for the animals, but it is also a little disconcerting. "They hiss a lot. They don't like it," Morris says.
He proves his point with Lucifer. As Morris rubs jelly on the giant lizard's belly and moves the ultrasound device around, the animal gets grumpy. Morris soon decides Lucifer is a "he" after failing to find female organs. This is good news for Lucifer, who might have become even more upset if his name had been changed to Lucy.
Morris would rather have a better method of determining sex. "You'd rather not make a diagnosis of sex based on the absence of a structure, but it does work."
Next on the examining table is Diamond, who doesn't have to change her name, either. The doctor discovered her ovaries during the ultrasound and took blood samples.
A high testosterone level in the blood indicates a male. And if testosterone is any indication of maleness, Komodo dragons are off of the macho charts because they have so much.
Researchers in Florida are trying to determine sex from an egg. If successful, it would be the least invasive and most effective method.
Komodo dragons are found on only four small islands in Indonesia. One natural disaster could destroy the species. To save to the dragons is to save their habitat, researchers say, because they breed more effectively in the wild.
The Indonesian government has made a concerted effort to protect the dragons by putting them in Komodo National Park. But that doesn't shield them from the threat of fire or some other catastrophe. That's why researchers are so intent on finding effective ways to breed them in captivity.
Related Sites
- Dragon Doings - Komodo Dragon newsletter from the National Zoo
- Komodo Dragon fan page
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