Footage from South Australia shows younger siblings don't just have a tougher time of it in the human world – it's not that great in the marsupial world either.
In the video, filmed in Adelaide, two koalas are seen fighting over a gum tree.
The younger koala struggles to climb the tree, screaming in fear as a bigger koala drags it down.
Despite its valiant efforts it was eventually pushed out of the branches and knocked to the ground, where it sits and screams.
After recovering its strength the smaller koala launches its second loud attempt to climb the tree, only to be thrown to the ground once more.
But it all turned out okay in the end – the vocal little marsupial reclaimed the tree after the sun set, where it was finally able to settle down without screaming.
Koalas tend to call with a low grunt or bellow, usually communicating aggression or as a part of sexual behaviour. The crying scream as heard in the video is made under stress or to communicate fear.