Whale earwax forms like yours does: A gland secretes oily gunk into the ear canal, which hardens and accumulates into a solid, tapering plug. In the largest whales, like blues, a plug can grow up to 10 inches long, and looks like a cross between a goat’s horn and the world’s nastiest candle. Fin whale wax is firmer than blue whale wax, bowhead whale wax is softer and almost liquid, and sei whale wax is dark and brittle. But regardless of size or texture, these plugs are all surprisingly informative.
As whales go through their annual cycles of summer binge-eating and winter migrations, the wax in their ears changes from light to dark. These changes manifest as alternating bands, which you can see if you slice through the plugs. Much as with tree rings, you can count the bands to estimate a whale’s age. And you can also analyze them to measure the substances that were coursing through the whale’s body when each band was formed. A whale’s earwax, then, is a chronological chemical biography.
Stephen Trumble and Sascha Usenko from Baylor University have worked out how to read those biographies. And they’ve shown that whale earwax not only reveals the lives of their owners, but the history of the oceans. Hunting, abnormal temperatures, pollutants—it’s all there. If all of humanity’s archives were to disappear, Trumble and Usenko could still reconstruct a pretty decent record of whaling intensity by measuring the stress hormones in the earwax of a few dozen whales.
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“I think this is going to revolutionize our studies of whale biology,” says Kathleen Hunt from Northern Arizona University, who was not involved in the work. “Whale biologists are used to gleaning tiny bits of information from samples like a single blubber biopsy, one or two fecal samples, or a few photographs scattered over years. An earwax plug is more like 200 samples in a row, taken from the same animal, every 6 months, for its whole life.” They’re like the ice cores that climate scientists use to peer back into the Earth’s distant past.
There’s more at the link.
It’s amazing how much information can be derived from seemingly inconsequential sources. I’d never have thought of ear wax as being anything other than an unwanted excretion! One question, though . . . what size Q-tip for whale ears? Inquiring minds want to know!