Nuclear Bomb Pulses Reveal 400-Year-Old Greenland Shark is World's Longest Living Vertebrate
Greenland sharks, who can live up to 400 years old, have recently broken records as a team of international scientists discovered that this species is officially the world's longest living vertebrate.
Who are the Greenland Sharks?
According to the study published in the journal Science, Greenland sharks (also known as gurry shark or grey shark) grow extremely slow at only one centimeter per year. Their average length is five meters, but it can grow as long as 20 feet.
An Unusual Nuclear Method
In order to determine the Greenland sharks' age, scientists used the shark's rate of growth. They also used another very unusual method -- carbon dating from pulses left by nuclear bombs.
In the mid '50s, nuclear bomb testing was prevalent, and until now, these bombs still have pulses of carbon-14, which the scientists used to correlate radiocarbon dates with the shark length.
"Who would have expected that nuclear bombs [one day] could help to determine the life span of marine sharks?" cold water physiologist Michael Oellermann, who was not involved in the study, told Science.
By using this method, John Steffensen, Julius Nielsen and other researchers determined that one of the Greenland sharks they observed was 392 plus or minus 120 years old, making it the world's longest living vertebrate -- two decades older than the previous bowhead whales.
The Secret to the Shark's Long Life
"We were blown away by the lifespan of these sharks. Frankly, we sort of looked at this at first and asked ourselves, OK, so where did we go wrong?" biologist Peter Bushnell told Popular Mechanics.
Oellerman believes that the Greenland shark's longevity may be attributed to their cold water environment. Cold water can result to a lower metabolic rate, with slower growth and biochemical activity.
To learn more about Greenland sharks, check out the video below.