The koala diet is almost exclusively eucalyptus leaf of which they will eat a variety depending on availability and location. They do however eat some wattles, bottle brush as well as casuarinas and Melaleuca quinquinerva (a paper bark) used for medicinal digestive purposes. They need to consume about 500 gms of leaf a day. They will eat the several varieties prominent in their home range.
Eucalyptus is toxic to most creatures. The koala’s specialised digestive system isolates toxins in the liver and excretes them as waste. A joey in the pouch will feed on the female version of this specialised waste called “pap” at around 3 to 4 months of age to build the necessary bacteria to digest eucalyptus. As eucalyptus leaves are low on nutrients and hard work to eat, koalas are fairly sedentary, sleeping high in trees during the day and waking up to feed, mate and travel at night as well as at dawn and dusk.
Interesting fact: Koalas, particularly males, are often quite mobile during the day so look out for them, particularly during mating season.