Squid, cuttlefish and octopus are considered to be the most intelligent invertebrates. That means, what they lack in backbone they make up for in the the concentrated ganglia department. Considering what they eat, intestinal fortitude too.
Check out the faq at this site:
http://www.nhm.ac.uk/hosted_sites/tcp/
http://starryskies.com/Artshtml/dln/11-99/squid.html
excerpt from the second link >Scientists guess that giant squid are probably very intelligent, since their close cousins, the octopus, are the most intelligent invertebrates known. A large part of the squid's brain is dedicated to its enormous eyes -- each of which is about the size of a human head!<end of excerpt
I know most Americans don't eat squid, cuttlefish or octopus very much, but E. Asians do, including raw forms. It's also popular in Mediterranean cultures. One of my favorite dishes is stuffed squid cooked in tomato sauce and red wine Greek style.
If you aren't a vegetarian (good luck to you if you are), squid and octopus are a good form of protein. There is some cholestoral, but not much fat (though I'd be the last to deny the importance of fat in diet--cook in olive oil for example). And if you are troubled by the murder of such beautiful and intelligent creatures, you can be consoled by the fact that these creatures repopulate quickly. The Japan Sea off of Fukui doesn't yield very much seafood anymore, but with one exception: the squid. And octopus is always cheap and widely available; the favorite way to eat it is 'takoyaki', which are octopus fritters. This is a very proletarian dish and shows that Japan had fastfood long before McD's got here.
Charles Jannuzi