Big bird feathers: Emu, Cassowary, Ostrich, and Rhea

What are the similarities and differences between big bird feathers – the feathers of the largest birds on earth?

The Emu, the Cassowary, the Ostrich, and the Rhea are large flightless ratite birds. The Emu is from Australia, the Cassowary is from northern Australia and New Guinea, the Ostrich is from countries in Africa, and the Rhea is from countries in South America.

Their wings have no keel (anchor) on their sternum (a long flat breastbone) to connect to their wing muscles, which means that the birds can’t fly. Therefore, their feathers are mainly decorative. 

Their feathers have no feather vane, which means that they do not need to oil their feathers. They have no preen glands. Instead of preening (cleaning) their feathers with their beaks, they usually clean their feathers with sand. 


Their feathers have no barbules, which are little hooks. Flying birds have small hooks that connect their feather barbs together (the barbs grown at an angle). Having hooks makes the feathers lock together in a smooth, flat structure for flying. 

Big flightless birds have soft, fluffy feathers, because the feathers don’t have barbules, and barbules are tough and strong but not soft and fluffly.

Also, their bones are heavy and solid, unlike the hollow bones of flying birds, which is another reason why they cannot fly.

Southern Cassowary
Greater Rhea

Photographer: Martina Nicolls


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