Scientists say a large shark found in British waters lives longer than any other vertebrate in the world.
Some Greenland sharks, slow-moving giants which can be more than five metres long, have been found to be 400 years old, according to new research.
They have an average life expectancy of 272 years, which is longer than other species known for long life, such as turtles, tortoises and some whales.
The Greenland shark is the oldest vertebrate in the world
The scientists worked out the age of the shark by using a radiocarbon dating method previously used to establish the age of whales.
They examined eye lenses from 28 female Greenland sharks measuring between one and five metres long, which had accidentally been caught in fishing nets.
They measured a life expectancy of almost four centuries.
The new research, led by Julius Nielsen from the University of Copenhagen and Greenland Institute of Natural Resources, has been published in the journal Science.
"Greenland sharks are among the largest carnivorous sharks on the planet, and their role as an apex predator in the Arctic ecosystem is totally overlooked," said Mr Nielsen.
"By the thousands, they accidentally end up as by-catch across the North Atlantic, and I hope that our studies can help to bring a greater focus on the Greenland shark in the future."
The massive shark has a heavy cylindrical body and a short rounded snout, according to the Shark Trust.
It can be found off Scotland, in the North Sea and in parts of the English Channel, as well as the east Atlantic.
The Shark Trust says it lives in depths ranging from coastal shallows to more than 1,200 metres.
It eats fish and crustaceans, as well as mammals including seals.
The new reserach says the only creature to live longer than the Greenland shark is the ocean quahog, a type of edible clam which has a life expectancy of more than 500 years.
Previous research suggested the shark grows at a slow rate, of around 1cm each year.
Female Greenland sharks may not reach sexual maturity until they are around 156 years old, the team found.
Its flesh is poisonous because of the presence of a toxin which produces effects similar to extreme drunkenness.
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