Vienna zoo panda twins continuing to 'develop splendidly'

Giant Panda Yang Yang and her twin cubs which were born on August 7, 2016, are seen in this still frame taken from a surveillance camera footage dated August 22, 2016, released on August 23, 2016, in a breeding box inside their enclosure at Schoenbrunn Zoo in Vienna, Austria. Schoenbrunn Zoo/Handout via REUTERS

VIENNA (Reuters) - The twin panda cubs born at Vienna's Schoenbrunn Zoo turned 16 days old on Tuesday and are said to be fit and healthy. Releasing a video of mother Yang Yang holding the tiny cubs in her paws and licking them, the zoo said the giant panda was "extremely relaxed in her care" of her babies, which were continuing to "develop splendidly". "The young pandas stretch, wave their little paws in the air and make first tentative efforts to crawl on their mother's tummy," zoo director Dagmar Schratter said in a statement. "The pink tinge is also increasingly replaced by black and white fur and they are looking more like miniature pandas every day." Visitors hoping to catch a glimpse of the cubs, whose progress is shown daily on a video screen at the zoo, will have to wait before they make their public debut. "The next big step in the development of the panda twins is the formation of their auditory sense which takes place at about five weeks of age," Schratter said. "It will be the end of the year before they can really crawl and leave the breeding box." (Reporting By Reuters Television Editing by Jeremy Gaunt)