I need the research if you have an answer. I also have an important wager on the answer. The more highly evolved the animal, the more complex is the brain structure.
Human beings have the most complex brains of all animals.
Evolutionary forces have also resulted in a progressive increase in the size of the brain. In vertebrates lower than mammals, the brain is small. In meat-eating animals, particularly primates, the brain increases dramatically in size. The cerebrum is responsible for intelligence and reasoning. The cerebellum helps to maintain balance and posture.