Page 48 - Engineering in Nature

Engineering in Nature

branches, in the same way that we would hold a broom handle, and
again allow it to climb upwards.
Another feature that allows koalas to live comfortably in eucalyp-
tus trees is the special design of their stomachs. Eucalyptus leaves are

poisonous, though the koala bear's special stomach lets it feed on
them. The tree also provides the koala's needs for water. In doing all
this, the koala makes use of medical science on the one hand and the
biochemical factory in its body on the other.
Let us consider the koala's attributes in order:

• The Koala's Medical Knowledge
There are more than 600 species of eucalyptus in Australia, but ko-
alas make use of only 35 of these. For the koala bear, the eucalyptus is
not just a shelter, but an important food source. It's no exaggeration to
say that the eucalyptus is actually its sole food, which also serve the
koala as medicine.
Eucalyptus leaves possess a number of medicinal properties. They
contain enteric oil, a chemical that is deadly to a great many animals.
Yet the koala's liver is capable of neutralizing this oil, which is also the
source of the koala's characteristic smell.
Some of the oil, which spreads over the whole body mixes with
the air, and some enters into the body, causing parasitic insects to
drop out of the animal's fur.
The harmony between the koala and the eucalyptus does not end
there, since thanks to the eucalyptus leaves, the koala also regulates
its body temperature.
The chemical substances in eucalyptus leaves vary from tree to
tree. Indeed, two different types of leaf can be found on just one tree.

Yet just as if it had received medical training, the koala selects those

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