Academic Review 2024

12 ST EDWARD’S, OXFORD

This indicates that O. orca can process information a fraction faster than T. truncatus. This suggests that sudden inputs can be dealt with faster and more efficiently in killer whales, so that they thrive in their environment that bit better, potentially adding to the aspect of intelligence. Another part of the cerebrum, found in the cerebral cortex is the insula (Dingman, 2022). The insula is in a hidden location in the lateral sulcus, a well known crevice in the brain. The insula is dedicated to functions and feelings such as emotion, perception, and pain (Dingman, 2022). The insula of O. orca has been declared the world’s most detailed, controlling the abnormally high emotional connections observed in the wild between killer whales and between them and different species (OrcaNation, 2019). A harrowing example of the emotional connections between killer whales is shown by their ‘human-like mourning’. A mother whale in the Pacific Northwest lost her calf after it unfortunately died 30 minutes after birth and she carried her dead infant over an estimated 1,000 miles for two weeks and three days (Main, 2018). The vast size of the insula of T. truncatus is only similar to the insula of primates (Jacobs, Galaburda, McFarland, & Morgane, 1984). They show some of the highest levels of intelligence in the animal kingdom. As described in this section, the EQ scale puts T. truncatus 161.09% above O. orca. This scale also puts humans at the top and scientists believe it is the most accurate scale to use showing how far the human species has come. However, O. orca have slightly more gyrified brains and therefore process information more rapidly, leading to better awareness of their surroundings. At this point, I must be open minded about intelligence, and how it relates to these species’ different behaviours. Diana Reiss (2012) stated ‘Brains can only tell us so much, and it really is their behaviour that gives us an indication of what these animals, what their intelligence is like.

BRAIN STRUCTURE AND ITS FUNCTIONS The brain consists of three main parts: cerebellum, brainstem, and cerebrum. These contribute to the autonomic functions of an organism as well as voluntary movements (Hopkins Medicine, 2022). An organism’s social interests link to the cerebellum, it controls their behaviour and it also causes the initiation of movement (Hopkins Medicine, 2022). This does not affect intelligence. The brainstem controls autonomic movements like blinking and certain reflexes such as swallowing and vomiting (Hopkins Medicine, 2022). These are background functions in many species; these factors do not affect intelligence levels, therefore will not be considered. The biggest part of the brain is the cerebrum. The cerebrum can be split into four main sections. The frontal lobe: involved with the senses, problem solving, and speech. The parietal lobe: connected with pain, language, and spatial understanding. The occipital lobe: associated with vision. Lastly the temporal lobe processes speech and memory (Hopkins Medicine, 2022). The cerebral cortex is the name given to the outermost part of the cerebrum. Containing gyri and sulci, ridges, and folds (Hopkins Medicine, 2022). Certain characteristics of a cetacean brain vary causing contrast in intelligence. Gyrification is the number of cortical wrinkles, allowing the nerve cells in the brain to be closer together therefore allowing greater speeds of neural transmission, as well as less energy used up in the process (OrcaNation, 2019). Greater gyrification provides increased amount of information processing, the optimal use, control, and speed at which the data is understood (OrcaNation, 2019). The Gyrification Index (GI) puts: • Orcanus orca at 5.70 (the most gyrified brain in the animal kingdom) • Tursiops truncatus at 5.62 (OrcaNation, 2019)

“ A harrowing example of the emotional connections between killer whales is shown by their ‘human-like mourning’. ”