Sir David Attenborough thinks that dolphins are deep thinkers.
Why? Well, apparently they are able to herd fish:
Dusky dolphins use teamwork to corral huge shoals of anchovies into a tight ball, while some bottlenose dolphins use walls of mud or tail-thrashes to scare mullet out of the water. Off the coast of Brazil, dolphins have even formed a successful fishing partnership with humans.
Yeah, because inborn fish-herding behaviour could never evolve in a species that lives solely on fish, could it?
And isn't Sir David just a teeny bit fazed by the fact that it is possible to write zoology textbooks specifying which species uses which herding tactic?
They can communicate too:
As highly social mammals, dolphins possess amazing communication skills using sound and body language to keep in touch. In Hawaii, they can even understand us, through a special sign language that the scientists have developed.
But again, it doesn't seem to occur to Sir David that this is simply the dolphin using a program in its brain that evolved so that dolphins could send a fixed repertoire of signals under predetermined conditions. We humans might see their meaning as saying “food over here” or “Hey, baby! How about doin' the horizontal mambo?”, but to them it's just ... well that's the point isn't it? What is the point of imagining that there is such a thing as what it is like to them? Why aren't similar documentaries made about the deep thoughts of our (or for that matter the dolphins') immune system, as it tracks down bad cells and spares the good, with a sophistication, ability to ‘learn’, and complexity of communication that makes a dolphin look like a floating beer can by comparison.
It might be fun to have a companion sentient species to talk to. But dolphins are dimwits, their immense intellectual achievements in the field of putting frisbees into baskets notwithstanding. They show a very limited ability to learn language but the language always refers to moving objects around and putting them in specific places. If there was a dolphin that was capable of having a conversation about art, philosophy, music, physics, mathematics or even Big Brother, that would be a sign of intelligence. But there isn't. Thinking involves being able to create new and better ideas. There is no reason to think that dolphins learn, in the human sense of the word, any more than a word processor learns science when a scientist types a paper which it then reformats and prints out. Dolphins are just slotting parameters, provided by humans, into a program hardwired into the dolphin brain by evolution. The only creativity involved is that provided by the gullible humans who interpret the resulting behaviour.