Cetaceans Have Complex Brains for Complex Cognition: e139

Recently, Manger [8] made the controversial claim that cetacean brains are large because they contain an unusually large number of thermogenic glial cells whose numbers increased greatly to counteract heat loss during a decrease in ocean temperatures in the Eocene-Oligocene transition. [...]he argues, cetacean brain size could have evolved independently of any cognitive demands and, further, that there is neither neuronal evidence nor behavioral evidence of complex cognition in cetaceans. [...]there was no need for odontocetes to respond to these temperature decreases with either change in body size or brain size. [...]changes in brain size (and body size) in odontocetes were likely due to factors other than oceanic temperature change.