Yesterday I drove up the coast to Pigeon Point to do a little poking around. I had originally planned to search for little stars, survivors that had made it through the most recent outbreak of wasting syndrome. But I got distracted by other things and gave up on the stars, for now. I need to do some thinking about the best way to find tiny animals in a very complex 3-dimensional habitat.
I did spend quite a bit of time turning over rocks in tidepools. The most common critters I found were the usual suspects–porcelain crabs, limpets, snails, the odd sculpin or two, and chitons. One rock yielded a gold mine: five chitons of a species I didn’t recognize (which doesn’t mean I haven’t seen it before, just that I didn’t immediately know its name) that demonstrated a most interesting behavior.
© Allison J. Gong
I turned the rock over and watched as the chitons ran away from the exposed surface onto the other side. Yes, RAN. I’ve never seen a chiton do anything this fast. Chitons, for the most part, lead apparently inactive lives. When we do get to see them in their natural setting, at low tide, they are usually scrunched down hard on the rock waiting for the water to come back. Obviously they are much more active when covered with water, but we don’t get to see them then. In the lab, where they can be immersed all the time unless they crawl up the walls, they do wander around a bit; however, to see a chiton do much of anything requires time-lapse photography.
Don’t believe that a chiton can run? Well, get a load of this:
This is in real-time, not sped up. Watch the chiton push a limpet and the snail out of the way. Okay, I’ll grant that a limpet and a snail are not the strongest obstacles one could face when trying to flee from the light. But you can’t deny that this chiton seems to be feeling a sense of urgency.
This species, Stenoplax heathiana, spends its days buried in sand on the underside of rocks. It comes out to feed at night, not on algal scums as most chitons do, but on bits of algae that drift by and get caught between rocks. Apparently the chiton can be found exposed in the very early morning. I’m going to have to try finding some this spring when we get our morning low tides back. Anybody want to come with me?