Interesting article. I went on a real animal intelligence kick a few years ago when I read Eugene Linden's <i>The Octopus and the Orangutan</i>. The books full of fascinating stories of animal emotion, intelligence, and tool use. (My personal favorite was the Orangutan who learned how to pick the lock on his cage and kept the improvised pick he used secreted behind his bottom lip, thus allowing him to escape several times before handlers got wise to what he was doing.)<p>On a separate note, Wikipedia may have its flaws, but it certainly excels at giving accessible, digested information on pretty much every conceivable topic. This is a perfect example of that: a complex topic adequately summed up in a few digital pages.