Reuters: Don't take my word for it...Dr Paul Manger of Johannesburg's University of the Witwatersrand is making the claim.
Brains, he says, are made of neurons and glia. The latter create the environment for the neurons to work properly and producing heat is one of glia's functions..."Dolphins have a superabundance of glia and very few neurons ... The dolphin's brain is not made for information processing it is designed to counter the thermal challenges of being a mammal in water," Manger said.
He goes on to cite the fact that a goldfish will jump out of a fishbowl but a dolphin will never jump out of its cage, because "the thought would simply not cross their unsophisticated minds". Considering that goldfish die when they jump out of their fishbowls I'm not sure it's a great example...
It's an interesting story, not just because of the content but because it's a science story that's not based on a recent study. It's just some guy with a beef against dolphins.