Why do dogs zig-zag?

I was walking one of my dogs, well, because he refuses to go outside since it's been raining. My girl dog is outside catching raindrops, building mud castles, excavating dinosaur bones and coming into the house on freshly cleaned carpets to show me what a great time she's having. It was while I was walking my sissy dog that I noticed something peculiar. He walks left to right then back again.

What's up with that? In an open field, on the sidewalk, heck anywhere there was room, he walked zig-zag. A quick search on google didn't pull anything of relevance until I found a story of a person who had bought a new bike. While riding, their dog was in front running, you guessed it, zig-zag. The dog was herding the m. Like a sheep dog that runs back and forth to bring the sheep in after a long day of grazing - my dog was herding me. Well, maybe not intentionally me - since I was the only present during the walk, I'm thinking it was me.

My male dog is a corgy mix - short legs and very furry. Looks like a miniature bear. Growls like a bear and talks like one. However, he's a sissy when it comes to putting his paws on any surface that has water on it. Got lots of reading to do on "the herding" instinct this coming week...

1. Wolves and coyotes walk in a fairly straight path.
2. Domestic dogs tend to zig zag
3. working on number three still...