SSS 2009-02-02（在线收听）

This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute.

If you have a dog, you know you gotta walk it. But do you know how it walks? Well, if you have no idea which foot Fido puts forward when, you’re in good company. Because according to a study published in the journal Current Biology, even places like natural history museums get it wrong half the time.

Studies published back in the late 1800s showed that all four-legged animals walk the same way. They start by moving forward their left hind leg, followed by the left front leg. Then they repeat the sequence on the right-hand side. Different animals differ in the timing of their steps.

The reason they walk that way is for stability. Lifting one leg at a time leaves three feet on the ground, forming a nice stable tripod to stand on. But not everyone seems to know that, even folks who should. Scientists looked at 300 depictions of animals walking—in museums, anatomy texts, and even children’s toys. And they found that nearly half the time these images get it wrong. For a toy, that kind of inattention to detail might mean that Rex has a tendency to roll over. But for museums to mess up like that? They just don’t have a leg to stand on.

Thanks for the minute for Scientific American's 60-Second Science. I'm Karen Hopkin.