'We were all just in awe': A stranding in Ireland sheds new light on the long, slow, ice-cold life of a deep-sea shark

Greenland sharks are thought to live for around 400 years. What can they teach us about the secret to longevity?

The ocean's dead often wash up on the storm-battered west coast of Ireland. But in April 2026, a group of researchers and volunteers stood on the cloudy shoreline of County Sligo, Ireland, and marvelled at the sight of a species that had never been stranded here before – a dead Greenland shark. 

Judging by its size – around 3m (10ft) long – the grey-beige animal lying on the tidal flats was over 150 years old. It would have been born in the age of Queen Victoria and US president Abraham Lincoln, when three-mast sailing ships crossed the seas, and the car hadn't yet been invented. 

By Greenland shark standards, that's pretty young.

"It's such a pity. This guy – it took him 150 years to get to the point where he could have reproduced, could have contributed to get the population on track, and may not have had the chance," says Emilie De Loose, a marine biologist at the Irish Whale and Dolphin Group.

The Greenland shark, the longest living vertebrate on the planet, can live for around 400 years. As baby sharks, some of the ones swimming around today may have been contemporaries of Shakespeare – though the exact length of lifespan is still subject to debate, with estimates ranging from roughly 300 to 500 years.

"We were all just in awe," says De Loose. "It's so mind-boggling to think how long that animal lived, and what it might have seen." 

While sad for the species – and the shark – the stranding, and the necropsy that followed, were an opportunity to shine some light on a species shrouded in mystery.

A visitor from the deep

"There is something very intimate about working with dead animals, because you really get to know the species," says Jasmine Stavenow Jerremalm, a PhD researcher in marine ecology at University College Cork in Ireland, who took part on the necropsy of the shark. "Dead animals can tell us a lot about the living ones."

The first challenge was getting the shark to a lab. Greenland sharks are among the world's biggest sharks, measuring up to 5m (16ft). This one weighed over 200kg (440lb). The group on the shore covered the body with seaweed, to prevent seagulls and other animals from pecking at it. The next day, in a recovery operation overseen by the National Museum of Ireland, a crane hoisted it onto the back of a lorry and took it to a regional veterinary lab.

A day later, protected by masks, gloves and overalls, a group of researchers from a range of organisations and institutions, including the museum, started examining the shark in a well-ventilated space.

"When it's an animal that could be a few hundred years old, there could be anything in that animal, so for health and safety, you want to be sure you follow good routines," says Stavenow Jerremalm. "If it's an animal that's lived for that long, bacteria or viruses from very long ago could be within that body", and then suddenly get exposed through the necropsy, she explains. "It's important to be mindful that we don’t know why this animal died, and which potential diseases it could have within it."

When it comes to Greenland sharks, researchers are still trying to answer a vast range of questions – from how these animals manage to live for such an extraordinarily long time, to basic facts around their existence.

Greenland sharks are slow-swimming, solitary scavengers and predators. They feed on carcasses but are also known to catch prey such as seals, and have even been observed "hoovering" up their prey. Powerful suction allows them to suck prey into their mouths, swallowing it whole.

"Greenland sharks are very slow swimmers so they are mostly thought of as scavengers that feed off carcasses. But sometimes they seem to opportunistically manage to catch live, fast-swimming prey," like seals, says Lily Fogg, a postdoctoral researcher in evolutionary biology at the University of Basel in Switzerland. "Since Arctic waters can be........

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