5 Feb 2013
The four cubs, named Mumbai, Maja, Melody and Mona Lisa, weighed between one and two pounds each when they were born, and have been gaining weight rapidly ever since.
White tigers are extremely rare, with only 300 in the world.
The zoo's director, Herbert Eder said that the cubs' arrival had caused great excitement: "We were all so happy when they were born, I felt like a new father myself.
"The most important thing is that the mother is very nice and is taking care of her young ones very well."
Now five weeks old, the quadruplets will stay with their mother for a year.
