Koalas don't need to drink - they get high on eucalyptus leaves instead.
Arf, arf, arf.
Koalas do NOT get high on eucalyptus leaves.
I rather think this was a joke (evidinced by the Arf arf arf bit), a play on drink as in relieve your thirst and drink as in to imbibe alcohol. I do not think it was a serious attempt to posit that koalas get a "high" from Eucalyptus leaves.
Actually soup, believe it or not it is a common held misconception, and one I have seen in various travel forums or heard from tourists.
No, and that's fair enough - but on Googling sites to draw this to peoples attention, I was surprised at how many people still think that koalas get high on eucalyptus. It was merely for informative purposes only.