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Why Can't an Emu Fly?

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The emu has wings and feathers, but he can’t fly. He’s the second largest bird on earth, after the similarly flightless ostrich and is native to Australia. Emus were once able to fly, but evolutionary adaptations have since robbed them of that gift. A quick look at the emu would suggest he is too heavy to fly, but the reasons are more complex.

Short Wings

An emu’s wings are smaller than a crow’s, measuring approximately 7 inches. The wings are so small that they’re concealed by the bird’s body plumage. The wings are small and they’re not particularly well built. For a bird to achieve flight, he needs strong wings that can propel his body mass upward, the feathers are structured to give strength to the wings without weighing them down. The poor emu’s wings are adorned with poor quality flying feathers that looks more like shaggy fur.

Fast Legs

The emu can’t fly, but he can run. Capable of achieving speeds of up to 30 mph, his long powerful legs are his only mode of transport. He doesn’t run to hunt though, as his diet consists mainly of bugs and vegetation. He runs to escape danger.

Easy Pickings

Throughout history, the emu has been fortunate enough to be surrounded by food. He is a ground-feeding bird and is more capable than most other species of birds at turning his food into body mass. Because the species is flightless, extra body mass isn’t a disadvantage, so the emu has been able to thrive; those who were best at bulking up survived better than those who didn’t.

Lazy Ancestors

Scientists at the Australian National University believe the emu evolved to be flightless because his ancestors got lazy. With few living predators, scientists believe that the emu’s only real threat was from dinosaurs. When the dinosaurs became extinct, the emu had no reason to be able to fly, so it didn’t. Over time, emus with weaker flying ability would have been removed from the gene pool by dinosaurs. But they managed to survive and reproduce, because the threat was gone.