Points and Snippers

Perhaps you meant pincers, or nippers? suggested Pliny the Elder. Not snippers, he added, pointedly.

I'm sure it said snippers in the Biodiversity Gallery, I insisted. However, they probably meant pincers. I'm sure they didn't mean us to think the crab used gardening snips. Where would a crab find those, for goodness sake?

My point exactly, said Pliny. At least we can understand how a sponge crab might lay its hands on a sponge.

Perhaps you mean pincers, or nippers, Pliny, I suggested. Not hands.

Point taken, said Pliny, with a watery smile.

I've been thinking about the sponge crab, I continued. Why does it need a sponge for protection ? It has a hard shell after all. What is a sponge good for? Soaking up water. Well, how useful is that to a crab?

Good question, said Pliny thoughtfully. What made you think of it?

I thought of it when I was walking home through the parklands afterwards and it began to rain. My hair was getting wet. I had a plastic shopping bag in my handbag, so I got it out, unfurled it and held it over my head. I remembered the sponge crab, then, with its bright yellow sponge on its head.

On its back, surely.

Yes alright, on its back. And I thought that a sponge would be a lot more useful to me than a plastic shopping bag, because the rain was dripping over the edges of the plastic bag onto my shoulders. And then I thought it wouldn't, once it had filled up.

So it would only have been better, up to a point?

Up to a point, yes. But if I'd been a crab, I might have had the opposite view.

How so?

Because the plastic shopping bag would have covered me completely.

Assuming that, as a crab, you would care.

Yes, assuming I would care.

Ahh, said Pliny. Natural history! It certainly makes you think.

Sponge Crab and Decorator Crab

I was telling Pliny the Elder about my visit to the new Biodiversity Gallery in the SA Museum.

It was good, I said.

What did you learn? he asked.

That put me on the spot.

Umm, I learned ......

I tried to remember what I had learned. I had seen a great deal. A number of stuffed birds and snakes that I seemed to have seen before in earlier galleries. Drawers full of spiders and beetles and butterflies on pins. Numerous excited children and their parents. But what had I learned?

Suddenly I remembered the brightly coloured models of the Sponge Crab and the Decorator Crab.

There is a crab called the Sponge Crab, I said knowledgeably. It carries a sponge about on its back as a shelter. The sponge grows with the crab. If the sponge gets stolen, the crab will try very hard to get it back. If it can't, it will find itself another sponge.

Fascinating, said Pliny the Elder. What else?

There is another crab, called the Decorator Crab, that is equally strange, I told him. This crab uses snippers to snip off bits of seaweed that it finds, and sticks them to its back with glue that it secretes from a gland. It does this as a means of camouflage.

Snippers? said Pliny sharply. Where does it get the snippers?

Oops! I said. I can't remember that.