Dolphins, and a lot of whales, are very very smart. My thinking is, - lot smarter than chimpanzees.
Our intelligence doesn't correlate well to theirs, so we have a hard time understanding them.
But dolphins understand and respond to trainers intentions very fast. There's no doubt that they are very smart.
Chimpanzees might be challenged by some birds too. Experiments with a rather small parachite, have demonstrated as good or better language and communications skills, and understanding of abstract concepts, as any sign language gorilla or symbol language chimp. Very impressive for such a small volume brain. It doesn't need signs or symbols either, it can speak.
- And don't forget elephants.
In general, I think all animals are a lot smarter and more 'conscious' than most people or even science give them credit for. They just experience the world differently and communicate differently. Of course, good dog owners have known this for ages...