Whoever said they don't like surprises has clearly never witnessed a panda giving birth to a pair of unexpected twin cubs.
Yang Yang, already a mother, gave birth in a dark nesting box away from the prying eyes of Austrian zookeepers.
Because pandas like their privacy when giving birth, zookeepers didn't realize until a week later that she had actually given birth to two cubs.
The little ones, who are only 4 inches long and weigh 3.5 ounces, will not be named until 100 days after their birth, because the chance of survival for both babies are only 50 percent in their first few weeks, experts said.
If all goes according to plan, Yang Yang and her two babies will appear in public for the first time in four months.
Yang Yang has previously given birth to three other cubs, Fu Long, Fu Hu, and Fu Bao.