With a pointed nose, humped back and around the size of a rabbit, the southern brown bandicoot was once widespread in south-east Melbourne. These small marsupials are also ecological engineers. In fact, a solitary bandicoot can turn over 3.9 tonnes of soil in a year, helping spread beneficial fungi, increasing nutrient turnover, and improving water penetration into the soil. However, these little critters are getting harder to find, and their numbers have dwindled - they are now listed as nationally endangered.