What do you think of this fact?
Tortoises, whales, parrots: when you think of the senior citizens of the animal kingdom, a shark probably isn’t the first thing that comes to mind. But the Greenland shark holds the record as the longest-lived known vertebrate. These animals can apparently live for around 400 years.
Reading age in the eye
For many sharks, you can count growth rings in their calcified vertebrae to figure out their age. But the Greenland shark is a “soft” shark without those vertebrae. A team led by marine biologist Julius Nielsen found another way and published it in the journal Science in 2016.
The researchers studied the eye lenses of 28 sharks and dated them using radiocarbon. Nobody had ever tried that on fish before. Traces of nuclear bomb tests from the 1950s and 1960s even helped: they showed up in only 3 of the 28 sharks and served as a time marker.
The result: one large female was about 392 years old, give or take 120 years. That puts the range between 272 and 512 years. Even at the low end, the shark beats the previous record holder, a bowhead whale estimated at 211 years.
Life in slow motion
The extreme age fits the laid-back lifestyle. Greenland sharks grow less than 1 centimeter per year and cruise at just 0.34 meters per second. Relative to their body size, that makes them the slowest fish on record. They don’t reach sexual maturity until they’re around 150 years old.
They live in the cold waters of the Arctic and North Atlantic, usually 100 to 1,200 meters deep. Adults are often 4 to 5 meters long.
Not every expert is fully convinced. According to Science News, Steven Campana of the University of Iceland is waiting for more research before he signs off on the 400 years.
When you live this slowly, there’s clearly no rush to get old.