World’s Biggest Birds Are Stellar Dads and Unusual Lovers

When it comes to child care and mating, ostriches, emus, and the like are, well, odd ducks.

When Nathan Young asked “What’s the difference between an emu and an ostrich?” Weird Animal Question of the Week decided to explore the whole group to which those birds belong, the flightless ratites.

As you’ll see, these birds are odd ducks (though there isn’t a duck in the bunch).

The ratites include African ostriches and emus, cassowaries, and kiwis, all of the South Pacific and greater and lesser rheas of South America.

All ratites lack a keel, or an extension of the breastbone where flight muscles attach, says Rebecca Kimball, an evolutionary biologist at the University of Florida.

(Related: "Why Fly? Flightless Bird Mystery Solved, Say Evolutionary Scientists")

Flight is a great way to avoid

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