Koalas are very independent animals and prefer to live alone (Sotzek 1997).  Although more than one koala sometimes lives in the same tree, each occupies their own branch.  The only koalas that spend large quantities of time together are mother koalas and baby koalas.  (Sotzek 1997).   Thus there is very little inter-species interaction.




Koalas have a handful of natural predators, which include wild dogs, goannas, dingoes, predatory birds, and pythons (PBS Nature 2013). They avoid these predators by predominantly staying up in trees, obscured by branches (Grosvenor 1998).


Although koalas have natural predators that impose a threat, their biggest threat is humans (PBS Nature 2013).  Previously, koalas were hunted by humans for their thick fur coats.  However, in 1930, laws were put in place to prohibit hunting koalas (PBS Nature 2013).  These laws are still in tack today, but a new and more deleterious threat currently endangers the survival of koalas.  Koalas’ homes are being destroyed by humans (Sotzek 1997).  Because the koala has such a limited diet, the destruction of their habitat is detrimental to their species’ survival.  When eucalyptus trees are cut, the koala loses it’s home and food supply (Sotzek 1997).  Fire has also destroyed many of the Australian forests that contain eucalyptus trees (Grosvenor 1998).  In addition, Koalas are killed in traffic collisions (Grosvenor 1998).  If interventions don’t take place, koalas are likely to become endangered.  Organizations, like the Australia Koala Foundation, are making vast efforts to perverse the koala. 



Koalas have some unique interactions with bacteria.  As noted in the nutritional section, koalas require a vast amount of bacteria in their digestive system in order to break down their toxic and hard to digest diets (Encyclopedia of Life 2013).  This demonstrates a mutualistic relationship, as the bacteria are given food and a livable environment, and the koala is getting help with the break down of its diet.   A more detrimental relationship between bacteria and koalas is the prevalence of Chlamydia.  Chlamydia is caused by the bacterium Chlamydia trachomatis and is considered the main pathogen of koalas.  It can cause blindness, infertility, and eventually death (Natterson 2012).  It is a parasitic relationship, as the bacterium invades the koala for a stable environment, and the koala is harmed.  Peter Timms, along with his Queenland University of Technology colleagues, have been developing a vaccine to treat Chlamydia in koalas.  Timms hopes that his research will not only help koalas but also provide valuable information and direction in developing a human vaccine for Chlamydia. (Natterson 2012).