That article compares dolphins to chickens and goldfish. While I doubt the level of intelligence that some people attribute to dolphins, I haven't ever seen a goldfish or a chicken do a trained complex acrobatic maneuver for food, or wipe a mark off of its body after recognizing itself in a mirror.

> When goldfish are placed in a bowl, he explains, they at least try to escape by boldly jumping out,

I don't think jumping out of a fishbowl is a particularly smart move...

> whereas dolphins that have been captured in nets won't even think of jumping to freedom.

What?!

Maybe the book was not good, but this does not change the fact that dolphins have dialects, variations to adapt the environment, and can call directly other dolphins using individual names. Many species of cetaceans have languages, for sure. There is a bottlenese, an orcanese and a commondolphinese. Probably more than one of each in fact.