What mammal has the largest brain of any animal?

The mammal with the largest brain of any animal is the sperm whale. Its brain weighs about 7 kilograms on average, making it more than five times heavier than a typical human brain and the largest known brain among living or extinct animals.

The sperm whale's enormous brain is housed inside its distinctive block-shaped head, which can make up roughly one-quarter to one-third of the animal's total length. The brain is especially associated with the whale's sophisticated underwater sensory life, including powerful echolocation clicks used to locate prey in the dark ocean depths.

A larger brain does not automatically mean greater intelligence. Brain size must be considered alongside body size, neural organization, and the amount of brain tissue devoted to different functions. The sperm whale has a lower encephalization quotient than humans and some dolphins. It is also the largest toothed whale and a deep-diving predator, capable of hunting squid more than 2,000 meters below the surface.