Inside A Sperm Whales' Head

 Sperm whales' heads are filled with a mysterious substance called spermaceti. 

 Picture from Monterey Bay Aquarium

Scientists have yet to understand its function, but the fluid—which hardens to wax when cold—helps the whale alter its buoyancy so it can dive deep and rise again.

The Superb Sperm Whale

Sperm Whale (Physeter catodon)

When Herman Melville wrote Moby Dick, a story with a bull sperm whale as a hero, he made an good choice. These colossal marine beasts may grow up to 67 feet and have the largest brain of any modern or extinct animal! Not only does it have a massive brain, it is the largest toothed whale. Though it was hunted intensively until about 1980, the maximum known age is 77 years.