They are very picky eaters and only consume leaves from a limited number of eucalyptus species, about 50 out of the 600 or so species that exist.
This is because eucalyptus leaves contain toxins that are harmful to most animals, but koalas have evolved a special digestive system that allows them to break down these toxins.
Here are some interesting facts about their diet:
* They eat a lot! A koala can consume up to 1 kg (2.2 lbs) of eucalyptus leaves per day.
* They don't drink much water. They get most of their moisture from the leaves they eat.
* Their diet is low in nutrients. Eucalyptus leaves are low in protein and fat, so koalas must eat a lot of them to get the energy they need.
* They have a slow metabolism. This helps them conserve energy and survive on their low-nutrient diet.