The overall size of non-human animals' brains is not related to their intelligence. Humans are considered to be more intelligent than sperm whales, even though sperm whales have brains that are more than five times heavier than humans. In general, the ratio of brain size to body size is a more accurate way of measuring an animal's intelligence, but even this only places humans ahead of animals. The size of one's brain does not correlate with intelligence in humans. There are some geniuses in their field who have smaller-than-average brains, while there are others who have larger brains.