Why do birds like the ostrich and the emu have wings though they cannot fly?

Emus live all over Australia and although they are classed as birds, they are one of the very few birds that can't actually fly at all. They are members of a group of birds called ratites. Other ratites include the Southern cassowary of Australia and New Guinea, the kiwi from New Zealand, the ostrich from Africa and the rhea from South America.

Ratites have wings but the bones in their chests do not have the capacity for flight muscles, which is what a bird needs to fly. Although the emu does not actually weigh as much as it appears (30-45kg), its wings are also too small by comparison to lift it.