Move over, tortoises. The Greenland shark has taken the crown as the world’s oldest animal with a backbone. Recent tests of a female shark’s eye lenses estimates her age at 392, writes Science magazine.

Greenland sharks are part of the sleeper shark family Somniosidae. This family of predators is unique for their low activity levels and semmingly non-aggressive nature. These sharks are mainly found in the colder waters of the Acrtic and subarctic, where water temperatures range between -0,6 and 12 degrees Celsius.

Despite the cold these sharks are massive creatures – their size often compared to white sharks. Greenland shark can grow up to 6,4 metres in length and weigh about 1 000 kilograms, this makes them longer than white sharks, but much lighter, as their white-bellied cousins weigh about 1 950 kilograms.

The Greenland shark’s longevity has been the topic of interest to scientists for many years, since it was discovered that they grow by only about 1 centimetre per year. The discovery was made in the 1930’s when a fisheries biologist in Greenland tagged more than 400.

More recently marine biologist John Steffensen from the University of Copenhagen tried to age a Greenland shark by counting the growth rings on a piece of backbone retrieved from it. When Steffensen could not find any rings, he consulted Jan Heinemeier, an expert in radiocarbon dating at Aarhus University in Denmark. Heinemeier suggested to Steffenson that measuring the various forms of carbon in the shark’s lenses, which could give a better estimate of the shark’s age.

Steffensen found the oldest Greenland shark was about 392-years old, plus or minus 120 years.

Video credit: Associated Press