Sperm whale
Brain

The sperm whale brain is the largest known of any modern or extinct animal, weighing on average about 7.8 kilograms (17 lb) (with the smallest known weighing 6.4 kilograms (14 lb) and the largest known weighing 9.2 kilograms (20 lb)), more than five times heavier than a human brain, and has a volume of about 8,000 cm 3. Although larger brains generally correlate with higher intelligence, it is not the only factor. Elephants and dolphins also have larger brains than humans. The sperm whale has a lower encephalization quotient than many other whale and dolphin species, lower than that of non-human anthropoid apes, and much lower than that of humans.
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