Listen to an interview with Murray Logan who spent many nights on Magnetic Island in north Queensland finding koalas to help with research on their habitat use and home ranges.
One of the interesting aspects of koala biology is that they are the only vertebrate able to live solely on gum tree eucalyptus leaves. Dr Murray Logan said koalas have poorest diets of any mammal. The real challenge in the koala diet is the toxic compounds in the leaves that resist insect attacks and are antibacterial. As herbivores rely on fermentation to digest their food anything that kills microbes is also going to make digesting and extracting nutrition from the leaves more difficult. One adaptation found in koalas that allows them to live on eucalyptus leaves is specialised gut flora.