How to tell the age of a 400-year-old shark
Media playback is unsupported on your device
Video

How to tell the age of a 400-year-old shark

A new study suggests that Greenland sharks can live to almost 400 years old. If true, it means they are the longest living vertebrates.

Julius Neilsen, marine biologist at the University of Copenhagen, tells the Today programme how they work out the age by carbon dating the sharks' eyelids.