Thursday, September 25, 2014

The other white meat

When a flatworm catches a snail on rock or glass, the snail resists strongly, but the flatworm wraps itself around the shell and twists and tugs at it, sometimes for several hours until the snail tires. The flatworm always wins.

But a limpet should be different; there are no corners on its conical shell for the flatworm to get a grip on. So when a big flatworm oozed over one of my limpets, I never expected this:

You're wasting your time, flattie! He's stuck tight!

The flatworm tries to insinuate itself under the edges of the limpet, but it has a seamless hold on the glass.

Nothing much happened for 15 minutes. The flatworm slid back and forth over the limpet, never managing to get under the edge. Then ...

Suddenly, the flatworm shrinks inward and yanks up; the shell separates from the limpet meat.

The shell is pushed off to the side, and ...

The worm slides away, carrying a nice limpet steak. The shell remains, still attached to the glass.

Total time: 25 minutes.

The little white swimmers are copepods. The flatworm, and some of the limpets and hermits have a pinkish tinge this week; they've been eating Violet Tunicates growing on blades of eelgrass. Most of the tunicates are now just white scars.

I always blamed the hermits and the big anemone for empty limpet shells. Sometimes one loses its grip on a blade of eelgrass, or is knocked off by a hermit, and comes tumbling down to the sand or the anemone's mouth. On the sand, they are unprotected, and hermits and the crab eat them quickly.

Now, I've added flatworms to the list of predators. Poor, inoffensive, hard-working, glass-scrubbing limpets!


  1. Vasha6:57 pm

    Holy hell, I hadn't realized a flatworm could be so strong.

  2. I know; they look like a soft paste, almost liquid. It's all muscle.

  3. You show me parts of the world that I've never seen .... thank you!


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