Eucalyptus leaves is the only food koalas eat. Although the leaves are poisonous to most animals, they have special bacteria that live in their stomachs to break down and digest them. Their diet includes up to one pound of leaves a day.
The koala has special teeth adapted for their eucalyptus diet. The majority of their front and back teeth act like scissors to chop the leaves into pieces suitable for digestion. Eucalyptus leaves have a fair amount of moisture hence koalas seldom drink water.
Plant specie information about eucalyptus trees indicate there are many different varieties in the wild. In fact each koala is particular about what kind they will eat. Baby koalas acquire their taste for specific varieties by adulthood. One of the main reasons koalas are endangered in some areas is the destruction of native eucalyptus forest habitats.
Eucalyptus leaves are high in fiber and low in nutrients. In addition to eating large amounts, koalas are able to survive on their diet since they have a slow metabolic system to conserve nutrients and energy. Since they have no natural predators in Australia, this adaptation is not to their disadvantage.
Koala information gathered from both wild and captive habitats suggest koalas live to be around 15 to 20 years.