Greenland sharks were aged using the lenses of their eyes

How I got here

Started with

How do you figure out the age of a shark?

Ended at

Ming (clam)

The Trail

1. “greenland shark 400 years how do they know” (google.com)
2. Greenland shark (en.wikipedia.org)
3. Radiocarbon dating (en.wikipedia.org)
4. Bomb pulse (en.wikipedia.org)

   nuclear testing spiked atmospheric carbon-14, a timestamp in anything that grew then

5. Ming (clam) (en.wikipedia.org)

   507 years old. died when researchers opened it to count its rings

What I came away with

Their vertebrae don't lay down growth rings, so a 2016 study radiocarbon-dated the core of the eye lens, which forms before birth. The largest shark came out at 392 ± 120 years, so somewhere between roughly 270 and 510. That makes it the longest-lived vertebrate known, even with the huge error bars. They seem to reach sexual maturity at around 150.

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