What makes their claws blue??

I love that question from ‘Carchin’.

Evolution or intelligent design, whichever you prefer!

That’s a great question actually, one I never thought myself. Here’s the story. Blue crabs are a member of the ‘swimming crab’ family. They have rear paddles on their hind-most legs for swimming. Their blue color is on their sides, claws, legs, along with bright white coloration on their undersides.

While they are swimming, predators are beneath them.  From below, predators probably find it harder to see them since the blue and white will blend in with the sky above. It’s camouflage while they swim!

And of course, they are olive green on top, so they blend in with the sea bottom when they’re not swimming.  It’s called cryptic coloration, a most useful adaptation found all over the animal kingdom.  Being dark on top & white on the bottom is really common for swimming animals.  It’s called countershading.

Gold star for ‘Carchin’!  First one ever for this blog!  Check is in the mail.