There may be sharks alive today that were born before Shakespeare.

Greenland sharks grow about a centimetre a year in icy Arctic waters. In 2016, scientists dated the lenses of their eyes. The oldest was estimated at around 400 years old, the longest-living vertebrate known.

Truth label: Established. Strong evidence and broad agreement among experts.

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How they dated it

The core of the eye lens forms before birth and never changes, so it can be carbon dated.

Slow life

They may not have young until they are around 150 years old.

Learn

1. A big range. The 400-year estimate has wide margins, from about 270 to 500 years.

Test yourself

Sources

• Greenland shark

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