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Author Topic: A funny thing about crabs...  (Read 655 times)

Offline P-Kasso2

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A funny thing about crabs...
« on: 14 November, 2016, 10:27:53 AM »

Red land crabs on Christmas Island on their annual march towards the sea to spawn. Click to enlarge.

Late yesterday on tv I caught a re-run of Attenborough's Planet II about the amazing annual march of the red land crabs on Christmas Island ...One and a half million bright red (un-cooked) land crabs suddenly all upped sticks and marched seawards on their perilous trek every year to spawn in the ocean.

And every single one of them was marching sideways. Which make me think.

Why do crabs all walk sideways? What's in it for them? Their eyes face forwards so why don't they walk forwards too? They'd be able to see threats and predators much better that way which, in evolution terms, is usually the name of the game.

So why did crabs evolve to walk sideways?
"I live in hope"