Koalas do not go underwater.
Koalas are arboreal marsupials and, while they can swim, it is not an activity they choose to do.
What I have heard is that you blow through a straw into water for as long as you can. If you do it enough then you will be able to achieve circulatory breathing.
All reptiles breathe using lungs, they cannot survive under water for a long time. Even if they spend their lives entirely in water, they have to often swim to the surface to take another breath.
how long can garter snakes stay under water?
they can't breathe under water
A female koala is pregnant for 33 to 35 days before giving birth.
They can stay under water for 10 seconds.
I can put my face under the water for 20 seconds
a few of the sea animals cannot stay under water for a long time.
as long as they want until they need to spout the water
How long baby koala bears stay with their parents can vary depending on how often the mother reproduces. On average, the koala bear stays in its mother's pouch for five to seven months.
I wouldn't try putting a dog under water and I don't know.
Without breathing, the world record is 22min With air bottles (scuba diver) or in a submarine you can of course stay longer. In a submarine when you have enough supplies, you can stay virtually forever under water.