Slashdot points to an Aljazeera (!) article about dolphin intelligence (or lack thereof). The article quotes scientist Paul Manger, who argues that since dolphins never think to jump out of enclosures such as holding tanks in aquariums, or tuna nets, they clearly aren’t very smart. After all, even a goldfish will jump out of its tank if you don’t put a lid on it.
Manger’s argument may be a little simplistic (“escaping” to suffocation is hardly an example of “intelligence”), but it does bring up an interesting point: are dolphins really as smart as most people seem to think? A Wikipedia article sheds a bit more light on the subject: Dolphins show complex social behaviors, they communicate with one another, they may use tools, and they may demonstrate self-awareness (though this research is disputed).
The evidence for dolphin intelligence appears to be much less clearcut than it is for other animals, especially primates. After all, plenty of “dumb” animals like fish are also social, and lots of animals have crude methods of calling to each other. The research on self-awareness and tool use is intriguing, but the results of those studies are hardly conclusive.
Dolphins may be cute, and they can be trained to do impressive tricks, but it’s doubtful that they possess humanlike intelligence.