I remember Roy Scheider in Jaws excitedly babbling, “We don’t even know how old sharks are!” And he was right–back when Jaws was made, nobody knew any reliable method for estimating the age of a shark.
But now scientists have estimated that a female Greenland shark is about 400 years old ( http://www.bbc.com/news/science-environment-37047168 ).
This is one of those things that makes you wonder, “Why didn’t anybody think of this before?” They used a radiocarbon test to estimate the shark’s age. Usually this is a test that’s used by archeologists. I never heard of it being applied to living tissue–but there’s no reason I can think of why it wouldn’t work.
The Greenland shark inhabits polar seas, sometimes swimming under the Arctic ice pack, and grows up to 24 feet long. Someone ought to investigate how the shark keeps warm. Whales and seals have blubber, polar bears have fur, the Borchgrevinck fish has a special chemical in its blood that functions as antifreeze; but the shark has none of these.
Some big sharks, like the great white and the mako, along with a few big fish like tuna, are functionally warm-blooded. This hasn’t been detected in any but a few species.
Anyhow, this shark that lives in horribly cold water has always fascinated me. Imagine swimming around under the ice for 400 years.
God’s creation always holds surprises for us.