One of the world's most critically endangered species of turtles has been bred in captivity for the first time. In May two baby Batagur baska turtles hatched at Schönbrunn Zoo in Vienna. The zoo, which already held four of the world's 18 known turtles of the species, announced the achievement last week.

The four adult turtles, including two pregnant females, came to the zoo in April from the collection of father-and-son turtle experts Reiner and Peter Praschag. The Praschags, who have published several key papers on the Batagur turtle genus, saved the four turtles from a cooking pot in India in the 1970s.

The species was once common in the rivers of India, Bangladesh and Myanmar, and their meat and eggs have long been considered a delicacy, which is what drove them into near-extinction in the first place.

The Praschags say they turned the rare turtles over to Schönbrunn Zoo for two reasons: "They grew to a size which was not easy to handle for us anymore," Peter Praschag told Scientific American. The zoo also had an appropriate nesting site, which the Praschags lacked at their private facility in Graz, Austria.

Thanks to the Praschags' research, the zoo was able to create what it called "exactly the perfect conditions for the females to lay eggs." Because the turtles are so rare in the wild, "we took temperatures from wild nests of the closely related B. affinis in Malaysia," Praschag says.

Zoo spokeswoman Barbara Feldmann told the Croatian Times: "These are the first human-bred Batagurs in the world and are a sensational breakthrough in the survival of this species."

In addition to the six turtles in Vienna, the remaining known B. baska turtles are held at the Mangrove Interpretation Center in Sajnekhali, India, the Madras Crocodile Bank Trust in India, and a temple in Burma (Myanmar). "Hopefully there are more in the wild," Praschag says, "but until today we couldn't get any evidence of a reproducing population."

Interestingly, much of the information and photos you'll find on B. baska online is not correct, including the that on IUCN's Red List of Threatened Species. The last major update to the Red List entry was in 2000, several years before Peter Praschag used mitochondrial DNA to reassess the phylogeny and taxonomy of dozens of south Asian turtle species, and in the process prove that most turtles believed to be B. baska were actually a different species, B. affinis. His team's research on the subject was published in the July 2007 issue of Zoologica Scripta.

The two new hatchlings will be left to grow in Schönbrunn's terrarium before being put on display in their aquarium this autumn.

Photo: Batagur baska, courtesy of the Asian Turtle Conservation Network