Aloha all:

A recent article by Paul Manger in Biological Review (2006, 81, 293-338) posits that the evolution of big brains in the Cetacea was a response to ocean cooling in the Oligocene to provide for more efficient thermogenesis.  To bolster this hypothesis, Manger argues that the big brains of the cetaceans do not support advanced information processing capabilities (i.e., the increases in brain size were not a response to the need for and advantages of advanced information processing capabilities).  He argues further that, in fact, cetaceans, dolphins included, are not very intelligent after all, and critiques negatively several studies reporting advanced or special cognitive skills in dolphins.  Unfortunately, there has been extensive publicity the press and television about "dimwit dolphins" that are really no smarter than rats, etc.,  etc. You may have seen or heard some of these reports.   A problem is that Manger's review of the cognitive literature is limited and includes little of the large body of contemporary laboratory and field data showing advanced cognitive skills in dolphins.   For those who are interested, and request a copy, I can send a PDF of a chapter I recently published that reviews much of the contemporary laboratory data.  The reference is Herman, L. M. (2006). Intelligence and rational behaviour in the bottlenosed dolphin. In S. Hurley & M. Nudds (Eds.) Rational animals? Pp. 439-468.  Oxford University Press.     For recent relevant fieldwork on bottlenosed dolphins, I highly recommend the chapter by Richard Connor and Janet Mann, Social cognition in the wild: Machiavellian dolphins? Pp. 329-370, published in that same volume.

Louis (Lou) Herman