>>40422647
Being mammals, koalas raise their joeys on milk (admittedly, one of the lowest milk yields to body ratio... There's a trend here).
When the young joey needs to transition from rich, nourishing substances like milk, to eucalyptus (a plant that seems to be making it abundantly clear that it doesn't want to be eaten), it finds it does not have the necessary gut flora to digest the leaves. To remedy this, the young joey begins nuzzling its mother's anus until she leaks a little diarrhoea (actually fecal pap, slightly less digested), which he then proceeds to slurp on.
This partially digested plant matter gives him just what he needs to start developing his digestive system. Of course, he may not even have needed to bother nuzzling his mother. She may have been suffering from incontinence. Why?
Because koalas are riddled with chlamydia. In some areas the infection rate is 80% or higher. This statistic isn't helped by the fact that one of the few other activities koalas will spend their precious energy on is rape.
Despite being seasonal breeders, males seem to either not know or care, and will simply overpower a female regardless of whether she is ovulating. If she fights back, he may drag them both out of the tree, which brings us full circle back to the brain:
Koalas have a higher than average quantity of cerebrospinal fluid in their brains. This is to protect their brains from injury... should they fall from a tree.
An animal so thick it has its own little built in special ed helmet. I fucking hate them.
Tldr; Koalas are stupid, leaky, STI riddled sex offenders. But, hey. They look cute.
If you ignore the terrifying snake eyes and terrifying feet.
