The songs and sounds of baleen whales are one of the ocean's most magical and haunting phenomena. Just listen to this humpback mother and calf together.
The beauty of these calls shouldn't distract you from the fact that they mean something, too. These aren't just tunes that whales are humming to themselves on a lazy Sunday. It is a method of communication. The calls provide everything from the comfort of knowing that loved ones are nearby, to an alert system, in times of danger or distress.
Scientists have long known that the calls themselves can travel long distances. But new research is showing that whale skulls are better designed to receive even the faintest calls than once thought.
Is there an echo in here?
Basically, the heads of large whales are giant, hollow chambers. Okay, not empty hollow. But whale skulls are open and vast enough to allow sounds to vibrate and amplify inside of them. This is kind of like how an echo builds inside an empty tunnel or room. Given that the ear bones of whales are fused to their skulls, scientists wondered: could their heads act like an antenna or satellite dish for collecting the calls of other whales?
To test the theory, researchers at San Diego State University used the preserved bodies of two baleen whales—a fin and a minke—and discharged a variety of different frequencies at their heads. They found the lower frequencies that matched those of real whale calls caused the best vibrations in the animals' skulls. Just as they thought, the skulls captured and amplified those sounds. Amazing!
Turn down that racket!
This study also sheds light on a real problem that whales face in the wild: ocean noise from large ships. Giant tankers make sounds that are on similar frequencies to whale calls. Scientists have long stated that as ships criss-cross the ocean, their noises confuse migrating whales, leading them astray and sometimes causing them to beach and get stranded.
Learning more about which sounds whale skulls best capture might help us develop ships and shipping routes that leave these massive marine mammals alone. After all, when your songs are that lovely, you don't want some big old boat messing up your playlist!