You’ve just mentioned one of the things that has annoyed me for many years.

The koala’s diet is mostly Eucalyptus, quite toxic. So they sleep for 20 hours a day, and are slow. This didn’t make sense to me because it would be a sitting target for predators.

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Working on building zkTLS infra/products. A ruthless empiricist and meme connoisseur.

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There are barely predators in Australia.
Apart from the Crocs, there's dingos, which aren't naturally occurring there. 
That's pretty much it.