My favourite marine animal, except that I am fascinated by all the other ones. Clippings come from Deep Intellect, by Sy Montgomery (Orion Magazine)
Octopus intelligence evolved when they abandoned their shell, enabling novel hunting and sheltering strategies.
Contrast with human intelligence, which is supposed to be driven by social needs.
He also offers a great description of the beasts:
“No alien is so startlingly strange. … an animal whose eight arms are covered with thousands of suckers that taste as well as feel; a mollusk with a beak like a parrot and venom like a snake and a tongue covered with teeth; a creature who can shape-shift, change color, squirt ink”
He later mentions that they can see (at least colors) with their skin