The fact is that nobody really knows how animals think. True, we're learning more about them all the time, but some of the information available now might not have been available when the books were written. K.A. seems to go by the stereotypes of how we think of animals rather than how that animal actually probably thinks, unfortunately. But, well, when you get down to it, our human perception of animals is really all we have to go on in the end, because until morphing technology is invented, we can't actually get into an animal's head. To be honest, I think the description of the dolphin's instincts was perfectly acceptable given the information available at the time.
Of course, there are a few just-plain-KASUs. Are ants and termites really as soulless as the books portray, while bees are seen as more like happy communists? And why are some prey animals (lizard, shrew, squirrel) portrayed as so full of fear that it's almost crippling, while others (rat, mouse, rabbit) were much easier to handle? Once you start analyzing the portrayal of animal instincts in the books, quite a few things start to fall apart.
And for that matter, elephant instincts were not portrayed nearly intelligent enough, even more so than the dolphins. Elephants invent games, honor their dead and actually seem to recognize what 'death' means, and research suggests that they are even aware on some level of their precarious habitat situation and are depressed about it. Yet there is hardly any mention on Rachel's part of her elephant morph being intelligent at all.
