Have you ever wondered about those lines in the creek? Do worms or snakes make 'creek circles'? Thanks to Ned Harris's investigative skills, I can blog with authority that these trails are made by dragonfly nymphs. Really. I'll give you this site for kids (which represents my current level of interest in dragonflies. You can google for more images and info if you want to learn more). Take a look in a shallow area in the creek (as you are peering over the side of a bridge, perhaps) and you are almost certain to find some trails. Now you can impress family, friends, and fellow canyon folks with your knowledge of dragonfly nymphs and what they do for fun.