The eucalyptus tree is famously the habitat of the koala in Australia, and also its only source of food. People do not generally eat eucalyptus leaves as food. But in some countries, they do ingest various forms and quantities, including eucalyptus oil, to treat a wide variety of health conditions. Although koalas are the biggest eaters when it comes to eucalyptus leaves, they are not the only diners at the tree.
The bluegum eucalyptus (Eucalyptus globulus) has many uses as folk medicine in different countries, according to the Purdue University Center For New Crops & Plant Products website. For example, Guatemalans apply the leaf shoots to the treatment of coughs and grippe, Jamaicans steep the leaves in teapots to treat colds and fever, Cubans use the essential oil against bronchitis, bladder and liver infections, among other conditions, and Mexicans chew the fresh leaves to strengthen the gums. Eucalyptus has a long homeopathic history, particularly in Asia and in Europe. In Britain, the practice was to ingest the oil as an aperitif for digestion. Nevertheless, eucalyptus leaves and oil are poisonous to humans and most animals in large quantities, according to Purdue University.
Detoxifying By Digestion
The koala (Phascolarctos cinereus) is actually a marsupial and not a bear. Because the koala spends most of its life in eucalyptus trees, it has very sharp and strong claws that help it to climb. An average koala day is spent resting and sleeping for between about 18 and 22 hours. The koala devotes most of its waking hours to eating eucalyptus leaves. Although eucalyptus leaves contain toxic chemicals, the koala is immune to them because its digestive system detoxifies the chemicals. Due to the koala's slow metabolic rate, the leaves it eats remain in its digestive system for a long time. This enables the koala to derive the maximum level of energy from the leaves, and to keep its need for energy to a minimum.
Koalas favor the leaves of only about 36 varieties of eucalyptus trees. At the San Diego Zoo, for example, koalas have a daily selection of leaves from different eucalyptus trees. Koalas eat between 1 and 1 1/2 lbs. of eucalyptus leaves per day.
Like the koala, the greater glider (Schoinobates volants) and the ringtail possum (Pseudocheirus peregrinus) also eat eucalyptus leaves, which are fibrous and do not provide much nutrition.
Food For Thought
There are more than 700 species of the eucalyptus tree, discovered in 1770 by British botanist, Sir Joseph Banks. Most species are native to Australia, but they also grow in New Guinea, Indonesia, the Philippines and northern California. Their common name, gum tree, refers to the sap that some species produce. In form, they range from small shrubs to large trees, between about 30 and 200 feet tall. The nectar from eucalyptus flowers feeds insects, birds, bats and possums.