Koalas are arboreal (tree-dwelling) marsupials, with a diet that consists exclusively of eucalypt leaves. Being marsupials, they are born extremely undeveloped and remain in the mother’s pouch during early development. The young begin to exit the pouch once fully-furred and at around 6 months of age receive a specialised ‘pap’ from the mother. This is a caecal excretion that contains high levels of microflora (hind gut bacteria). After pouch emergence young koalas begin to eat eucalypt leaves, but also continue to consume mother’s milk for a prolonged period of time (upto a year) until weaning is completed. Koala milk changes in composition over the course of lactation. We make two different stages of Koala Milk Replacer to cater for the different nutritional needs as the young develops.