The real story
Sharks have no reliable growth rings, so in 2016 a team led by Julius Nielsen looked at the eye. The lens core is built before birth and never replaced. Nuclear bomb tests in the 1950s and 60s spiked the carbon-14 in the ocean, which gave the team a time marker to calibrate radiocarbon dates against. The largest shark in the study came out at 392 years, give or take 120.
Greenland sharks live in near-freezing water, cruise at about 1.2 km per hour, and grow roughly a centimetre a year. Many carry a parasitic copepod on their eyes, and yet researchers have found seal and even polar bear remains in their stomachs. In Iceland the meat is cured into hákarl, because fresh it is toxic.
