Australia - Taking the Heat. Currently the most arid continent on Earth, Australia was once covered in lush rainforest. The animals living here today evolved some extreme survival strategies under the pressure of this catastrophic climate change. Now, red kangaroos must remain on the move, frogs lie dormant for seven years, koalas sleep 20 hours a day, and crocodiles go up to two years without food. Jeremy Northam narrates. Producer Clare Brook : Series Editor Tim Martin