1. Rico the Border Collie
Rico the border collie became famous after he was studied by psychologists who verified that he learned more than 200 words—“Rico’s vocabulary was thus broadly comparable to that of language-trained apes, dolphins, sea lions, and parrots.”
2. A Dolphin
3. A Chipanzee
4. Alex the African Grey parrot
—(http://www.alexfoundation.org/research/ … rvard.html)
Alex the parrot also learned the names of many objects and could retrieve them according to color or shape as well as the names of the objects.
I would have to say a dolphin. In the documentaries I have seen, dolphin could also recognise the shape of objects and retrieve them.
Also, dolphins are still studied and I think we have a lot to learn about them yet.
But that’s only my opinion, of course 🙂 and I have to say I am subjective, because dolphins fescinate me 🙂