Two Komodo dragons have hatched at the Sedgwick County Zoo in Kansas, apparently without the fertilization of a male.
The new-born dragons, both males, are believed to be the first in North America known to have hatched by parthenogenesis, which occurs naturally in some species, including invertebrates and lower plants. It happens more rarely in some vertebrates.
Two other known cases in which Komodo dragons hatched by parthenogenesis were at the London and Chester zoos in England in 2006.
The zoo in Wichita is having DNA testing done to document the mother's and the babies' genetic structure because of the remote chance that a male's sperm was stored on the female's body.
Komodo dragons are one of the few species capable of storing sperm, said Don Boyer, curator of reptiles and amphibians at the San Diego Zoo and species survival plan coordinator for Komodo dragons.
The Sedgwick County Zoo has had this female and one other since 1993, when they were less than a year old. They have been laying eggs since 2000.
"We never had a male dragon at the zoo. There were no tramps that came wandering through," said Nate Nelson, the zoo's curator of amphibians, reptiles and fishes.
One of the Kansas zoo's females, Gaia, laid at least 17 eggs on the nights of May 19 and 20, 2007. The females can lay as many as 30 eggs at a time.
Because the English zoos had documented parthenogenesis, the Sedgwick County Zoo checked to see whether the eggs were fertile. Only two of the 17 eggs were hatched — one on Jan. 31 and the other Feb. 1 — because the zoo does not have room for more dragons, Nelson said.
One is 16 inches long; the other is 17 inches. Komodo dragons can living 20 to 40 years. Males can reach 10 feet long and weigh as much as 200 pounds; females grow to between 5 and 7 feet and weigh as much as 125 pounds.
Komodo dragons are endangered, with between 3,000 and 5,000 in the wild. Eighty live in 30 zoos in North America.