NOVA | Portrait of Australia's unique evolutionary history. Why did Australia get a preponderance of pouched and egg-laying mammals? And, at the same time, precious few of the kind of mammal that dominates every other land in the world? Today no monotremes exist outside of Australia (and New Guinea), and no placental mammals that didn't fly or swim there—for example, bats or dugongs—exist in Australia except for rodents (which arrived only about five million years ago) and mammals that were introduced by people (who arrived by 60,000 years ago).
2007-05-23
Preferences...