Monday, December 10, 2018

Radula tracks

I had scrubbed the algae off the glass wall of the aquarium, but left a patch where a biggish limpet was feeding: I could get that later, when he moved on.

I stopped to watch him for a bit. He browses much like a cow on a hillside. Lick, swallow, lick, swallow, move on a small step, repeat. With each bite, his mouth opens, exposing the radula for a half a second, as scratchy as a cow's tongue. It scrapes from front to back and closes down again.

I took a few photos, trying to capture that split second when the radula is exposed. Not quite. But in a few of the photos, I noticed the pattern the limpet was creating.

The algae is splotchy where he hasn't fed yet, stripy where he's been.

Zooming in. See the radula tracks?

Zooming in still more. Each little scratch is about as long as the distance from the mouth to the back of the radula slit.

He's harbouring a few copepods; the shell is not clamped down tight to the glass unless he's disturbed, as when I clean around him.


  1. Do you only clean the front glass, giving the limpet grazing surfaces on the rear and side glass? Or is the limpet not able to keep up?

    1. I give the back only a quick scrub, from the top, leaving the bottom more or less as is. The limpets also have stones and shells in the tank to scrub, so they seem to be doing fine.


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