Koala and Tree Kangaroo were best friends, but during a drought Koala was lazy and refused to help Tree Kangaroo dig for water. When Tree Kangaroo finally found water in the dry streambed, Koala pushed him aside and drank it all greedily. Angry, Tree Kangaroo pulled Koala out by his tail, which broke off. This is why koalas now have short, stumpy tails according to Aboriginal Dreamtime storytelling.