Crabs have compound eyes!

[pressld2]

I expect at least two thirds of the WAB membership is now saying "Well, duh!" but I honestly didn't know this until today.



The things I've learned with a macro lens!

Dave P.

[Littlesparrow]

I didn't know either, so I've gain some knowledge to.

[Marineboy]

Amazing when you look at life in detail. Have you thought about when the crab molts? It de-calcifies its old shell and takes in water to split the shell at certain points, notably under the front edges of the carapace and at the base of each claw and leg. It then pulls, backs itself out of the old shell, as a "soft-shelled crab" - to touch, the whole crab feels soft and rubbery and it needs to hide away until its new shell hardens using the calcium in its system. Before moving off with a nice new hard shell, they will often eat the old shell - all of it!

Now the really amazing bit - when the crab molts, it pulls out from every bit of its old shell. That includes the claws, the legs, its mouth parts and yes, its eyes too. If you examine the shed shell from a molted crab you will see the true extent of what has happened. Not only has the external shell been shed, but the insides too, including the lining of all the gills. How it does that is beyond me!

[tcvarlh]

Originally Posted by pressld2

I expect at least two thirds of the WAB membership is now saying "Well, duh!" but I honestly didn't know this until today.



The things I've learned with a macro lens!

Dave P.

The wonder of what Athanasius Kircher thought when he first looked at vinegar thru' a lens, his 'innumerable multitude of worms' must have almost blown his mind. I can't imagine his amazement.

Strange planet we live on isn't it?

h

[pressld2]

Originally Posted by tcvarlh

Strange planet we live on isn't it?

Certainly is H. Strange, complex and often very beautiful.

Thanks for the details of the remarkable moult process Marineboy. This one had recently shed his skin and was, exactly as you describe, soft and rubbery to the touch. Unlike the larger one I found which managed to get hold of my finger with his pincer - ouch, that smarts!

I'll post some more pics in about a fortnight when I've finished my Scotland thread.

Dave P.

[Marineboy]

Ok, so it's not as sharp as pressld2's crabbie eye photo, but this is a wonderful pair of eyes. This is a close-up of the velvet swimming crab earlier in the post.