LOS ANGELES—The Los Angeles Zoo is trying to raise the population of female Komodo dragons, a giant and endangered lizard, by using a DNA test originally devised to identify the gender of bird eggs.
Swelling the female ranks would help close a gender gap in captive dragons in North America, which is home to 71 males, 46 females and six of the giant lizards whose sex remains unknown. It would also move the species closer to a self-sustaining and genetically diverse population, which scientists believe they would reach with 75 males and 75 females.
“Until now, we couldn’t control the gender of the dragons we hatched out — creating a lopsided male-heavy population,” said Ian Recchio, curator of reptiles and amphibians at the L.A. Zoo. “In captivity, it’s not uncommon for males to kill females, and females are prone to often fatal complications in pregnancy.”
Another reason for wanting to manage the number and sex of Komodo dragons hatched each year: They are expensive to keep and grow big enough to eat a human being.
“Komodos are like keeping tigers,” he said, admiring one of the two adults on exhibit at the zoo, a 10-foot male with a powerful tail, slashing stiletto claws and toxic saliva.
The procedure, first attempted at the L.A. Zoo, involves insertion of a fine needle into the leathery shell of a baseball-sized dragon egg halfway through its 260-day incubation period, and extracting a small sample of blood without killing the embryo. The sample is submitted to a laboratory for DNA testing to determine the sex.
Curators then put a dab of glue over the puncture and place the egg back in its nest in precisely the position it was laid. “Unlike bird eggs, reptile eggs cannot rotate at all during incubation,” Recchio said.