They are mainly active at night, making loud grunts or squeals to communicate with one another. They spend most of the day sleeping or resting. The rounded shape of Koalas is due to their very large intestines, which they need to digest eucalypt leaves. When moving, their rounded belly is visible and their long arms and legs can also be seen. Females have a backward-facing pouch.
Koalas live mostly in open eucalypt forests and woodlands.
In the inland part of their range they live in trees along watercourses. The eucalypts eaten vary from place to place, and Koalas are not found in areas that lack suitable food trees. Koalas mate in spring and summer. A month later, usually a single joey is born and continues to live in its mothers pouch for seven months. The young Koala then moves from the pouch and clings to its mothers back until it is strong enough to move around without its mothers help.