X-ray Megabat grey-headed flying-fox Fruit bat and Microbat ghost bat

" Let's not forget Australian mammals which are not marsupials, such as the grey-headed flying-fox (Pteropus poliocephalus) on the left and on the right, a ghost bat (Macro-derma gigas).

'All bats have three flight membranes that form the main body of the wing. The membranes are essentially modified skin stretched around a framework of bones,' writes Vogelnest and his co-author Graham Allan.

In the microbats, there is a fourth membrane which stretched the tail to the legs. This is used like a large air brake, allowing the bat to make abrupt changes in flight trajectory and speed. "

• abc.net.au / radionational / offtrack / echidna-innards-and-wombat-bones