Whilst sailing around the island you can be lucky enough to see world's most calm and biggest marine herbivorous mammal. You'll never take them for any other sea animal as the way they look is very specific.
The best place to watch them is Ningaloo, as has got the biggest population of sea cows in the world. Other places where these cute mammals were spotted are Fraser Island and Moreton Bay. However, as they are big seagrass lovers and prefer only the cleanest waters, sometimes you can be disappointed in not seeing any of them.