How many white koalas are there?

This is unknown. There is no species of koala that is white, but genetics can produce white koalas, which are known as albinos. There is only one species of koala, with some disagreement among biologists as to whether there are up to three sub-species. Albinos of any species of animal are a rarity, but they do occur, due to a absence of melanin. There is no way to predict when it will occur, of when it has already occurred. However, very few albino koalas survive to adulthood as they are easier prey for predators, and tend to have weaker immune systems.