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I want to talk about sparrows, one of the most common birds around the world. I noticed that when one slowly walks into them (so that they are not frightened enough to fly away), these tiny birds would jump away, rather than walk away, as if they are not able to walk.

Why is it?

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    $\begingroup$ This is the first result I've got in Google: "As for why sparrows jump, I suspect that they are perfectly capable of walking, but find hopping to be a more efficient way of moving across the ground in the irregular pattern that they generally prefer. This is partly a function of their small body size, since jumping is typically easier for small animals than for large ones of the same approximate shape." C Sullivan, Institute of Vertebrate Paleontology. $\endgroup$ – user24284 May 11 '17 at 1:16
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    $\begingroup$ Also, there is a good explanation here: theguardian.com/theguardian/2010/jan/27/… $\endgroup$ – user24284 May 11 '17 at 1:19
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There are several reasons:

  • Sparrows can hop away faster than they can walk away. In fact, when athletes run very fast, they are actually jumping with each leg, although not like sparrows.

So, why don't sparrows run like athletes?

  • The answer lies in the orientation of the hinge joint of their legs. Our hinge joint let's us turn our knee in the opposite angle than those of a sparrow's let's it. So, a sparrow, and animals like rabbits and kangaroos, find it easier to hop away than to run like us, when they need to jump.

  • Third reason is- just before a flight, all birds jump to power their flight. So, if a sparrow jumps away rather than walking away, it can convert any of these jumps into a full flight, in the case of an unexpected need.

But interestingly, have you ever seen any bird (with legs like that of sparrows) running away like an athlete instead of hoping away the way sparrows do?

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