Final answer:
Before a baby koala, known as a joey, can eat eucalyptus leaves, it must consume 'pap' to introduce necessary gut bacteria for digesting the tough leaves. This process is vital for the development of the joey's specialized herbivorous diet.
Step-by-step explanation:
Importance of Pap in Joey's Diet
Koalas are specialized herbivores and have a diet consisting exclusively of eucalyptus leaves. These leaves are tough and fibrous, requiring a specialized digestive system to break down the cellulose. A joey, which is an immature embryo at birth, is not born with the necessary gut bacteria to digest eucalyptus leaves.
By consuming pap, a paste of partially digested leaves from the mother, the joey ingests the essential bacteria and enzymes needed to digest eucalyptus leaves in the future. This is a crucial process for the development of the joey's digestive system and its ability to thrive on the eucalyptus-based diet of adult koalas.
Marsupials, like koalas, give birth to immature young that must complete their development in the mother's pouch, where they are protected and can nurse. The ingestion of pap is one of the developmental milestones that allow the young koala to transition from a milk-based diet to a leaf-based diet, ensuring its survival and integration into the ecosystem as a folivore.