Koalas are herbivores and eat mainly eucalyptus leaves (gum leaves) . They are very fussy eaters and have strong preferences for different types of gum leaves. In Australia, there are over 600 types of eucalypts, but koalas will not eat a large proportion of these. Within a particular area, as few as one, and generally no more than two or three species of eucalypt will be regularly browsed. Occasionally, they will eat the leaves from some other native Australian trees, and they also use certain trees just for resting in. Koalas consume around 200 to 800 grams of leaves each day, depending on their age, sex, and the species of eucalyptus available. They obtain most of their water requirements from the leaves, which can contain up to 50% water, and this removes the need for a koala to climb down a tree for a drink of water, except during very hot or dry periods. Eucalyptus leaves contain many toxic compounds similar to that of cyanide, which most animals cannot eat. However, koalas have special adaptations, body parts, or abilities that allow them to safely eat and digest eucalyptus. Koala teeth are especially adapted for their gumleaf diet. Their sharp front teeth nip the leaves from the tree, and their back teeth are shaped for cutting and grinding the leaves to extract the most nourishment.