That award for the animal has the biggest brain goes to the sperm whale. The average weight of an adult male sperm whale’s brain is 7.8kg compared to 1.4kg for a human’s.
The sperm whale’s signature shape makes it instantly recognisable, particularly its squarish head that seems disproportionately big – it comprises up to a third of the whale’s body length.
However, it’s another component of this vast cranium that historically meant the sperm whale was hunted. The spermaceti organ is filled with a pale, waxy liquid, formerly prized by whalers. It’s believed to be involved in buoyancy control and a sophisticated acoustic sensory system that enables these gregarious whales to relate to their complex, three-dimensional environment, and to form intricate social bonds.
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