Establishing what the perfect habitat for koalas is, is a complex issue, but a necessary one to understand if humans and koalas are going to live together. Koalas require the presence of certain tree species (mostly eucalyptus, and some non-eucalyptus) growing in suitable soils with adequate rainfall. There must be one or two primary species, preferred koala food trees, present within this suite of trees. The other very important thing is that koalas require the presence of other koalas – koalas live in societies and need to come into contact with other koalas. Understanding this interaction, and how koala home ranges work, needs to be considered. Also, koala habitats need to be big enough to support healthy koala populations and have extra area to allow for young koalas leaving their mothers.