Sally Lightfoot Crab, Galapagos

OK, enough with the black and white photography.

On our first island landing in the Galapagos, we saw these colourful beasties.  On the black lava, they stood out like, well, a Sally Lightfoot Crab, I guess.

Close-up of a Sally Lightfoot crab on black lava, in the Galapagos.

They might have evolved a coloration that would allow them to, you know, blend in a bit better.  They didn’t.

But they do have super hard shells.  Apparently, the shell doesn’t break even if dropped from a great height, so birds – the main predators – leave them alone.

But the babies have soft shells, and they also live on that black lava.  And whaddya know?  They’re black: The better to, you know, blend in, perhaps?  Not that it always works . . .

Galapagos heron with baby Sally Lightfoot Crab in beak.




    1. Isabel Gibson

      Barbara – I understand that bright colours and/or distinctive patterns have evolved in some insect species (some moths, maybe?) as a “Don’t eat me, you won’t like me” communication to predators. Not sure it’s an insect universal. I also understand that good-tasting moths mimic the bad-tasting ones – that is, the good-tasting moths that survive are the ones that look most like the icky ones, so that the original survival advantage is diminished. So the pattern changes again, and the race is on. I don’t have any idea why the Sally Lightfoot crab would have evolved this coloration. On that black lava, it does make them visible to conjugal partners, if crabs have such. Or maybe they’re just fashionistas.

    1. Isabel Gibson

      Judith – Thanks! I think I didn’t even see the baby crab until I downloaded the picture to my computer – sun-on-screen can be a dagnabbed nuisance.

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