Pocket Science – will all camouflaged cuttlefish please raise their tentacles?

[embed width="610"]http://www.youtube.com/watch?v=IznlT8XkmkY[/embed] Cuttlefish are masters of camouflage. Like their relatives, the squid and octopuses, they can change the colour of their skin to perfectly match a bed of pebbles, a clump of algae, or a black-and-white chessboard. I’ve written about their amazing colour-changing feats before, and the video above from the peerless Robert Krulwich shows what they can do. But their disappearing acts involve more than just colour and texture – they also use their tentacles to sell the illusion. Cuttlefish arms are flexible tubes of muscle and can bend all the way down their length. They can hang their arms in a clump in front of their heads, or splay them out in wavy zig-zags. Now, Alexandra Barbosa from the University of Porto has shown that these postures depend on what the cuttlefish can see. She placed ten young cuttlefish in front of striped backgrounds. If the stripes ran ...