Ostriches and emus have much in common. For a start, they are both absolutely enormous. At 2.5m tall and weighing 130kg, ostriches are the biggest of all living birds, and emus are close runners up.
Second, both are incapable of flight, with wings that serve only as balancing aids while running. Third, they are both kind of funny. Ostriches don’t actually stick their heads in the sand to avoid danger, but it’s a myth that somehow suits them. And it’s not for no reason that Emu was the name of a hugely popular puppet famous for his unhinged assaults on talk-show hosts and members of the Royal Family during the 1970s and 80s.
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What's the difference between ostriches and emus?
The differences are perhaps not as obvious as you might expect, considering they’ve been evolving independently for about 50 million years. Certainly their plumage is different. Male ostriches are black-white-and-pink birds: bright wing and tail feathers contrasting strikingly with dark body plumage and rosy, bare skin on the neck and legs. But that is true only of the males. The slightly smaller females are more uniformly brown. Male and female emus are more similar, with shaggy, brown plumage that hangs like a grass-skirt, and a sweep of blue skin on the neck.
Should you ever need to identify them from a footprint, an ostrich has two toes on each foot, while an emu has three. And if all you have to go on is an egg, an ostrich’s is creamy in colour, while an emu’s is green. (Ostriches lay the biggest eggs of any living bird – although a now-extinct bird holds the title of biggest ever egg – though, relative to body size, they are the smallest.)
The reproductive lives of both are rather eccentric. Among ostriches, many females will lay eggs in a single nest that is tended by a resident pair. And emus eschew sex-role conventions – it’s the females that do the courting and the males that do the bulk of the parenting.
Ostriches and emus live on different continents (Africa and Australia, respectively). They are, however, closely related. Both are members of a group called the ratites, which also includes other large, flightless (and funny) species, such as the rheas of South America and the cassowaries of New Guinea, but also the kiwis of New Zealand, which are much smaller, but no more capable of flight (and no less comical).
New Zealand was also once home to the extinct moas, which were only slightly smaller than the elephant birds of Madagascar (also extinct), the biggest birds that have ever lived, at well over 3m tall. Then there are the tinamous of the Americas. On the face of it, these grouse-like birds look nothing like ratites, and yet skeletal and genetic similarities suggest they are the closest living relatives of the moas. Intriguingly, tinamous can fly, which suggests that the other ratites became flightless only after they all went their separate ways.
Main image: both Getty
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