Evolution may not have favored intelligence. There may have been other factors more important: memory, hunting ability, communication, spatial awareness.
Some part of brain size relates to body size; it takes x amount of brain to run x amount of body. Humans are clearly above that amount compared to the rest of the primates. So are dolphins, and probably elephants and whales.
So, where does the excess go? Dolphins may be doing a lot of inter-relating and inter-communicating, via their sonar ability, which we haven't picked up on yet. Same for whales with their communication.
Morality is another question. What does it mean? Not bumping off your neighbors unnecessarily? I think for many definitions of morality many of our animal neighbors actually do pretty well in comparison to humans.
But its late and I haven't shaved...
I'll check in tomorrow for any responses.
Sad but true. Which is why saying a child molester is an animal is an insult to animals.