Koala, Australia Zoo. Leaves of the eucalypt tree make up most of a koala’s diet. It requires a lot of energy to digest these leaves so koalas are largely sedentary and sleep up to 20 hours a day to conserve energy. While there are some 6000 eucalypt trees, koalas are quite fussy and may only browse 2-3 types of trees and only eat the juicy tips of the leaves. Habitat loss through bush fires, land clearing or disease is the major factor affecting koala populations today. #australiazoo #koalas #thisisqueensland #brisbaneanyday #steveirwin #loveyouqueensland #australia #exploreaustralia