CT scan of whale head; fat in yellow, ear bones in magenta.
For us landlubbers, jiggling fat may just be an unsightly presence. For whales, jiggling clumps of fat in their jaws may pick up sound waves underwater, helping them communicate over long distances in the sea. We knew that dolphins and porpoises have “ear fats,” but baleen whales have not been as well-studied for one simple reason: their heads are just too big to fit into a scanner.
A new study looks at minke whales, a genus of balleen whales that top out at only seven meters long. (Tiny compared to 30-meter blue whales.) Scientists put six frozen whale heads, salvaged from beached animals, in CT and MRI scanners to analyze the soft tissues. Some of the heads were still too big, so the lower jaw had to be removed or excess flesh trimmed away. The scans and subsequent dissections showed a glob of fat sitting right next to the ear bones. While the anatomical evidence is compelling, the researchers admit they still have to show how exactly the fat works to help in hearing.