How can a Greenland shark live for hundreds of years?
The oldest Greenland shark dated so far was estimated at about 392 years old, give or take 120: the longest lifespan of any known vertebrate, read from the lens of its eye.
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A Greenland shark can live for centuries because it lives very slowly. It is an in water just above freezing, and it is sluggish, with the lowest swim speed and tail-beat frequency for its size of any fish, which most likely correlates with a very slow and extreme longevity. It swims at an average of just 0.34 metres per second.
Greenland sharks have the longest lifespan of any known . In a study published in Science in 2016, a team led by Julius Nielsen of the University of Copenhagen used on the eye lenses of 28 sharks. The centre of the lens does not change from the time of a shark's birth, so its chemistry can reveal the shark's age. The oldest was estimated at about 392 years, give or take 120.
Everything in the animal's life is slow. Greenland sharks reach sexual maturity around 150 years of age, and their pups are born alive after an estimated of 8 to 18 years. They can reach 6.4 metres in length, but a shark tagged in 1936 and recaptured in 1952 suggested they grow only 0.5 to 1 centimetre a year.
They live in the North Atlantic and Arctic Oceans and are poorly studied because of the depth and remoteness of their habitat. Their slow pace is also a risk: given ongoing fishing pressure, their low productivity and extreme longevity may severely limit their ability to recover from overfishing and bycatch.
Try it
A very slow atomic clock
- Carbon-14 atoms left
- 100 / 100
- Expected left
- 100%
- Half-lives passed
- 0
Challenge · Slide to 400 years, the age of an old Greenland shark, and see how few atoms have decayed. Then slide to 5,700 years, where about half are gone.
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Recap
Cold, slow and patient: a Greenland shark's age comes from a slow atomic clock, and its slow life makes it fragile.
💡 A trick to remember it · Cold water, slow clock, slow life: the less you hurry, the longer the candle may burn.
Surprising fact · Its age is read from the centre of the eye lens, which does not change from the time the shark is born.
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Sources (4)
No source, no claim. Every fact in this lesson (19 claims) cites at least one of these.