Experts say that Greenland sharks are the animals that live the longest on Earth.
Scientists used a special radiocarbon dating method to determine how old 28 Greenland sharks were. They found that one of the female sharks was very old – about 400 years old! This makes it the oldest known shark and vertebrate (animal with a backbone) worldwide. Before this discovery, the oldest known vertebrate was a bowhead whale that was 211 years old.
Julius Nielsen, the main researcher from the University of Copenhagen, said they thought they were studying a special kind of shark but were shocked to discover that the sharks were very old.
Greenland sharks are very big and can be up to 5 meters long. However, they only grow a little bit yearly, only 1cm. They can be seen swimming slowly in the cold deep waters of the North Atlantic.
The team believes the animals can reproduce when they are 4 meters long. According to this new information, this does not happen until the animals are 150 years old.
Scientists found that some sharks are older than 50 because of testing done in the 1960s. These tests made a lot of a special kind of carbon called radiocarbon. Fish in the ocean took this radiocarbon and passed it on to baby sharks. The scientists found that sharks with more radiocarbon in their eyes were born after the tests were done and are younger than 50 years old. Sharks with less radiocarbon in their eyes were born before the tests and are at least 50 years old.
The scientists then figured out a range of ages for the older sharks by using their size and information about how big Greenland sharks are when they are born and how fast they grow.
The sharks were very old. They may be 512 years old or 272 years old. But the most probable age for them is 390 years, according to Nielsen’s research.
But why do Greenland sharks live for a very long time?
Sleeper sharks live long because they have a slow metabolism and live in cold water. They move slowly through the icy waters of the Arctic and the North Atlantic, which is why they are called “sleeper sharks.” Researchers found that they eat seal meat, but it is believed that the seals were either sleeping or already dead when the sharks ate them because of their slow movement.
