Beluga whales, like many other cetaceans, are highly intelligent creatures. Cetaceans have remarkable depth and density of gyrification (Mortenson et al., 2014) and cortical sulcation in the brain that set them apart from those of terrestrial mammals (Marino et al., 2001). As part of the order Odontoceti, the beluga also exhibits a high encephalization quotient (EQ), which is a ratio that predicts the brain mass for an animal of a particular size in relation to many reference species. Though there were speculations that a high EQ value was related to the high cognitive demands of echolocation or the display of complex social patterns and behaviors, some studies suggest that the large Cetacean brain size may also thermogenetically counteract heat loss to the surrounding water (which would be extremely useful for migrations to habitats in the Arctic and sub-Arctic!).  A three-dimensional reconstruction and labeled illustration of a female beluga whale's entire brain (right) show an abnormally wide bitemporal section and a lack of olfactory bulbs (Fig.1). According to Marino et al. (2001), the beluga brain possessed a comparatively small corpus callosum and large cerebellum relative to the enormous hemispheres. (These size changes in brain areas, however, may also be related to making space for the blow hole.) The extremely large hemispheres could explain why beluga whales are able to demonstrate high hemispheric independence, such as being able to move each of their eyes independently or engaging in unihemispheric sleep (Mortenson et al., 2014). 

Additionally, MRIs of different sections of the beluga brain show cetacean divergence in brain organization, particularly in the cerebral cortex. Marino et al. (2001) found that there was a trend of increased sulcation of the orbital-to-occipital gradient that appeared with increased elaboration of the occipital-parietal region over the orbital region. In other words, the increased elaboration and specific combination of the occipital-parietal organization seen in the beluga is special amongst Cetaceans. Also, an observed auditory processing area called the inferior colliculus was proportionately bigger relative to the superior colliculus. The acoustic cortical enlargements and lack of olfactory sensors are possibly adaptations due to the fact that most whales don't need their sense of smell as part of their aquatic lifestyle, hence using the space to further evolve and develop more complex brain areas for audition.