Strings of periwinkles, tiny rock-dwelling gastropods, take advantage of low tide to make a crossing.

Lot of periwinkles, crossing over sand from one rock to another
Periwinkles, Littorina, on a sandy crosswalk | September 10, 2017

Here, they glide, en masse, from the tip of rock in the lower left, to new grounds on the rock stretching across the top. Pioneers mark the crossing with mucus. Less adventurous gastropodestrians follow along, single file.

Bunch of Littorina, putting some heavy grazing on a patch of Ulva grazing
Littorina, grazing down a tuft of Ulva

But not all the winkles are on the move. Nearby, some stay put, feasting.



    1. I know! I’ve seen it many times but it still amazes me. I worry about them on the open sand, but they must taste bad. The gulls don’t touch them.

    1. Good question! I tried not to step on any. They aren’t super fragile because they live on rocks that get pounded by waves. But they do seem vulnerable when they cross the sand, either to getting stepped upon, or eaten by predators. I have a question for you. I tried to go to your site and I got a note from WordPress that you deleted it. Did you start a new site?

  1. That first photo is intriguing. If you hadn’t mentioned what was happening I wonder how many people would have guessed correctly? It made me think of a scene in one of the “Lord of the Rings” movies when the hordes were descending on the keep. 🙂

    1. A memorable scene. I had a feeling, but I couldn’t put my finger on it. Thanks. I think you’re right, the photo itself didn’t convey what was going on very well. It took a few words. I’m grateful to you for reading them.

      1. I didn’t intend any criticism of the photo. Steve — I enjoy photos with a sense of mystery to them, that let me “see” something other than what is actually happening. 🙂

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