Whales' ear wax tells life story, tracks pollution

What's the best way to get to know a whale? No, not over a nice seafood dinner — apparently, it's through its ear wax...

 A team led by researchers from Baylor University extracted a foot-long rod of wax from the ear of a dead blue whale. That ear wax acts like a time capsule, tracking the chemicals present in the body as the whale aged. (Via Baylor University)

See, whales add a new layer of wax every six months, alternating between feeding and fasting seasons. Scientists can read those layers to see how old the whale is —  much like counting the rings on a tree.

They can also analyze the content of each of those layers to learn about the whale's life. For instance, the team knows this whale reached puberty just after it turned nine. Marine biologist Stephen Trumble told NBC News, at that age:

" ... the researchers saw a spike in testosterone levels, followed quickly by a spike in cortisol, a hormone released when an animal is stressed. ... 'It was mixing with the big guys trying to mate, and probably getting a rough time from the other males.'"

Ear wax can also show scientists the quality of the environment the whale swam in. This whale showed two separate spikes in mercury, meaning it probably swam through a polluted patch of ocean for a few months.

Chemicals are also stored in whales' fatty blubber tissue, but that buildup doesn't give researchers any clues as to when the whale was exposed to those chemicals. (Via NPR)

The team is planning to analyze some of the 1,000 or more ear wax specimens in museums around the world. Which is great for science, but really bad for nostrils — apparently they have a quote "pungent fishy smell." Lovely...

The study was published in the Proceedings of the National Academy of Sciences.

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