We will only mention, in this part, the central nervous system, which is made of the encephalon and the spinal chord. As a reminder, the encephalon is made of the cerebrum, the cerebellum and the brainstem. The overall is of a round shape and voluminous.

The brain is very creased and its weight is very substantial in proportion to the total weight of the body. The encephalon matches the shape of the skull, large and high.

The latest studies have shown and confirmed that the olfactory zone of the cortex (surface area of the brain) is still there but very small. In the other hand, the zone linked to the respiratory apparatus (specially the blowhole) is very developed. It receives the information via a major nerve called the trigeminal (trifacial nerve), which is also used to transfer information from the muzzle and the melon (echolocation information) SEE ECHOLOCATION. At the frontal level of the cortex, there is the motor zone. The acoustic nerve is also very developed, as is the zone in the cortex that links it. This demonstrates the importance of the sounds in the killer whales’ world. They are used for language and listening and also for echolocation purposes.

The nervous system of the killer whale is therefore very revealing. The animal evolves in a mainly sonorous and tactile world. SEE SENSORIAL SYSTEM