The Greenland shark is currently the longest-living vertebrate known on Earth, according to scientists.
The ages of 28 Greenland sharks were determined by radiocarbon dating eye proteins, and one female shark was estimated to be about 400 years old, making it the oldest known vertebrate on Earth, surpassing the previous record holder, a 211-year-old bowhead whale.
As Julius Nielsen, a marine biologist at the University of Copenhagen and lead author of the study, put it: “We had the expectation that we were dealing with an unusual animal, but I think everyone who did this research was very surprised to learn that the sharks were so old.”
Greenland sharks swim through the cold waters of the Arctic and North Atlantic at such a slow pace that they have earned the nickname “sleeper sharks.” Image credit: Julius Nielsen
Greenland sharks are huge creatures, capable of reaching up to 5 metres in length, but growing at a slow rate of just 1 cm per year. They can be found swimming slowly in the cold depths of the North Atlantic.
According to the research team, these animals only reach sexual maturity when they reach 4 meters in length, which, based on their estimated age range of up to 400 years, would not occur until they are approximately 150 years old.
A newly tagged Greenland shark returns to the deep, cold waters of Uummannaq Fjord in western Greenland. Image credit: Julius Nielsen
The study was based in part on radiocarbon levels in the sharks’ eye tissue, made possible by the large amounts of radiocarbon released into the ocean during atmospheric thermonuclear weapons testing in the 1960s. Sharks with higher levels of radiocarbon in their eye tissue were determined to be younger than 50 years old, while those with lower levels were estimated to be at least 50 years old or older.
The researchers then developed an estimated age range for the oldest sharks based on their size and previous data on the size of Greenland sharks at birth and the fish’s growth rates.
A Greenland shark swims near the ocean surface after being released from the research vessel Sanna in northern Greenland. Image credit: Julius Nielsen
According to Nielsen, the analysis has a probability rate of about 95 percent and determined that the sharks are at least 272 years old, but could be as old as 512 years (!), with the most likely age being 390 years.
But why do Greenland sharks live so long?
The longevity of these animals is attributed to their extremely slow metabolism and the cold waters in which they live. They move through the waters of the Arctic and the North Atlantic at a very slow pace, which has earned them the nickname “sleeping sharks.” Although seal remains have been found in their stomachs, the sharks are so slow that experts believe they must have devoured them when they were asleep or already dead.
The slower you go, the further you will go.
