The ancestors of ostriches and emus were long-distance fliers – here’s how we worked this out

Many flightless birds belong to Palaeognathae, a taxonomic group containing ostriches, rheas, emus, cassowaries and kiwi, as well as the tinamous of Central and South America. Scientists wondered whether different populations of flightless palaeognaths could have just drifted apart from each other along with the continents they lived on. One is that the flying tinamous are genetically closer to some flightless palaeognaths than they are to others. The dodo was a flightless bird that roamed Mauritius until it became extinct in the 1600s. New mammalian predators evolved slowly, over millions of years, giving these flightless birds plenty of time to evolve new ways to escape and defend themselves.