Wednesday, January 06, 2010

Did you know koalas have been around for tens of millions of years, and that they're bigger now and more abundant than any other time in their history? Neither did I :
Scientists have gained a glimpse into how the koala, one of the nation's most loved creatures, may have acted tens of millions of years ago.

....perhaps the most important finding to come out of the research is that never in their history have koalas had a period when they were so abundant as they are now.

The fossil remains of the extinct koalas....were about a quarter to a third smaller than today's koalas....

....24 million years ago, koalas and their close relatives, wombats, had long diverged on their evolutionary tree. Koalas were already creatures living in the forest canopy and specialising in eating leaves.

Perhaps the biggest difference between the ancient koalas and the modern variety is that it is clear from the fossil jaws and teeth that whatever the extinct creatures were eating it was nowhere near as tough as the leaves from present day gum trees.

The dominance of eucalypts in Australian forests is a relatively new thing - the result of the drying of the continent following a succession of ice ages. Koala teeth reflect this rarity of eucalyptus in ancient Australian forests.

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