The German company Festo makes a wide range of fascinating devices, many of which are based upon some kind of naturally occurring model of movement.
Among their products are various drones, and I have to say that the AquaPenguin is among my favourites.
The AirPenguin is obviously less based on actual penguin characteristics; still, it must be one of the most lovely and elegant drones created so far.
Still: stick a Hellfire launcher on that puppy and it'd make the most elegant Flying Robot of Death in the world.
A guy can dream, can't he?
(The BionicKangaroo, BionicOpter and SmartBird are also worth looking at.)