Board Thread:General Discussion/@comment-108.198.1.152-20130309164928/@comment-67.233.243.121-20130412000307

I think the idea is that they are so smart that we don't know about it. They are happier being left alone, and if we give them fish for doing dumb tricks, all the better.

Anyway, it is probably a reference to The Hitchhiker's Guide to the Galaxy books, which specfially stated that dolphins are the earth second most intelligent lifeforms. Humans are listed as third.