Before you ask, a rhea is like an emu. Or an ostrich. It has long skinny legs, an equally long neck and a round, plump body. Although it’s a bird, a rhea is not very good at flying. In fact, it’s useless at flying – it can’t fly at all (you are probably better at flying than a rhea). So it’s a bit weird that it has such big wings. Having said that, a rhea can run very fast. And when it runs, it spreads its wings. So maybe they are something to do with that. Next time you run, try holding your arms out like a rhea. It’s not easy.