So, yes: the cetacean brain is special, as long believed. This, we believe, will combat the loss of heat to the water-and help cetaceans to maintain a functional brain temperature. We conclude that the cetacean brain has a specialized thermogenic system that emerged around 32 million years ago. Glial cells are the housekeepers of the brain: they maintain the right micro-environment to support active neuronal functioning. We also found that between 30 and 70% of glial cells contain UCPs in cetaceans, while in artiodactyls the glial cells did not contain UCPs in readily detectable amounts. In the cetacean brain we found that almost three times as many neurons contain these proteins compared to their terrestrial relatives. This is achieved by activating uncoupling proteins (UCPs). This happens when mitochondria (organelles within the cell that produce energy) change their activity so that rather than producing adenosine triphosphate (ATP), for chemical energy in the cell, they produce heat. Brown fat cells can change their internal metabolic pathways so as to produce heat, warming up the body. The most commonly studied part of the body that produces heat through non-shivering thermogenesis is brown fat. We reasoned that this heat-producing system would have to use the process of non-shivering thermogenesis, a way to produce heat within cells rather than through muscular activity, as there are no muscles surrounding the brain.

Dolphin brain