Emus and ostriches became fat, flightless birds after dinosaurs died out and were no longer around to chase them, scientists believe.
An abundance of food and lack of predators following the mass extinction 65 million years saw previously flighted birds put on so much weight that they had to walk instead, according to research by Australian National University.
A molecular dating study revealed that the African ostrich, Australasian emu, South American rhea and New Zealand moa became flightless independently following the disappearance of dinosaurs.
Very cool.
