In Light Thickens a healthy koala joey (weaned but not yet adult) is plucked from its ideal habitat and instantly teleported to a foreign environment full of strange germs.  Within fifteen minutes it is “rescued” from a cardboard box and packed inside a backpack that’s been all over Europe without once being washed. After being subjected to varying temperatures and fed a monotonous diet of leaves from trees it did not pick out for itself, the koala is exposed to damp and cold while in the care of a person who treats it like a toy. 

How much suspension of disbelief would be required from the reader to have this fictional koala survive?    For the sake of entertainment, should I let the cute little animal end up scampering up a tree in some safe new habitat?   https://www.savethekoala.com/deborahtabartsdesk.html