How do we know how old sharks are? A new University of Georgia study looks at their DNA

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A new study from the University of Georgia looks to estimate the age of sharks by analyzing their DNA using a blood sample.

Previously, if you wanted to know how old a shark was, you’d have to read the rings inside their vertebrae like you might a tree.

That’s not always practical when a species is threatened or endangered.

Benjamin Parrott is an associate professor at the University of Georgia. He’s studying how DNA decays in sharks as an alternative method to see how old they are.

That could tell him how healthy the wider populations are.

"If reproductively mature individuals are not reproducing or all of those young are not surviving, then what you are going to see across the population is an aging population," he said. "Conversely, if individuals are not living very long, then you're going to see a very young-biased population."

Right now, the model is accurate, within a year or two of the sharks' average 30-year lifespans.