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Even a few decades ago, spotting a koala snuggled in a backyard tree was nothing out of the ordinary.

Blink, and a friend’s little bundle of semi-consciousness has grown to the size of a koala.

Like other organisms, some yeasts have evolved to be specialists -- think koalas, which eat nothing but eucalyptus leaves -- while others are generalists like raccoons, which eat just about anything.

More than a dozen koalas were convalescing in open-air enclosures, wrapping their woolly arms around the trunks of eucalyptus trees.

It is the birthplace of songbirds, the land of egg-laying mammals and the world capital of pouch-bearing marsupials, a group that encompasses far more than just koalas and kangaroos.