Scientists Finally Know How Baleen Whales Hear

A beached whale, a supercomputer, a scientific mystery solved

Baleen Whale
Denis Scott/Corbis

Scientists have been working hard to protect whales from underwater sounds, which they suspect can disrupt whale communication. But even as they’ve pushed for legislation to limit low-frequency sounds in oceans and bays, there’s always been a missing link. That’s because they have never really understood how whales hear at all—until now.

Marine biologist Ted W. Cranford wasn’t satisfied with past research, which relied on a set of inferences about the frequencies at which whales communicate and a few controlled underwater experiments. So he joined forces with Petr Krysl, a structural engineer, and set out to create an accurate computer model that might unlock the mystery of whale hearing.

Krysl and Cranford obtained the skull of a young but ill-fated beached fin whale and put it in a scanner originally designed for rocket motors. They used their scan to make a model that broke the anatomy down into Lego-like blocks, then mapped the relationships between each tiny element.

When they sent sound waves through their simulated skull, they could see how each little bone segment vibrated. But they weren’t done yet. Since the skull they modeled was that of a juvenile whale, they made another model that was three times as big. Then they had to find a computer that would actually be able to process the immense amount of data generated by their simulations.

Using a supercomputer, Cranford and Krysl ran their simulations for days, even weeks at a time. And it led to what Cranford has called “a grand discovery”—whale skulls seem to conduct sound, amplifying waves as they hit the skull and passing them along to the ear bones.

As scientists learn more about the incredible capabilities of baleen whales, their findings could cross over to toothed whales and even dolphins. Next up for Cranford and Krysl? See if their research applies to other species. But even if this structure is unique to baleen whales, says Cranford, it was worth the years of work:

This research has driven home one beautiful principle: Anatomic structure is no accident. It is functional, and often beautifully designed in unanticipated ways.

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